Antireflective film, polarizing plate and image display device

ABSTRACT

An antireflective film is provided and includes: a transparent substrate; at least one conductive layer formed from a composition including at least one transparent conductive polymeric material and a compound forming a cross-liking site, the compound having a plurality of cross-linking reactive groups, at least one of which cross-links with the transparent conductive polymeric material; and at least one low refractive index layer.

This application is a Continuation of U.S. application Ser. No.11/943,422, filed on Nov. 20, 2007, now U.S. Pat. No. 8,137,767 issuedon Mar. 20, 2012, which claims priority to Application No. 2006-316146,filed in Japan on Nov. 22, 2006. The entire contents of all of the aboveapplications are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an antireflective film, and further toa polarizing plate and an image display device each using the film.

2. Description of Related Art

An antireflective film is disposed on a display surface for preventionof contrast reductions due to extraneous light reflected off and imagesmirrored in the screen of every variety of image display device, such asa liquid crystal display device (LCD), a plasma display panel (PDP), anelectroluminescent display (ELD) or a cathode ray tube display device(CRT). Therefore, the antireflective film is required to have highphysical strength (including abrasion resistance), high transparency,high chemical resistance and high weather resistance (includingheat-and-moisture resistance and light stability). In addition,antistatic properties are required of the antireflective film in orderto prevent dust (dirt or the like), which depresses display'svisibility, from adhering to the antireflective film surface.

The antireflective film containing a conductive metal oxide is known(See JP-A-2005-196122). In the case of using a metal oxide as conductivematerial, the metal oxide density in a conductive layer must beincreased in order for the conductive layer to having the requiredconductivity. However, there are cases where addition of metal oxide inexcessive amounts adversely affects the transparency, hardness anddurability.

On the other hand, the antireflective film using a conductive polymer asconductive material is known (See JP-A-2005-96397). Such a film isformed from the conductive polymer produced by vapor-phasepolymerization of its monomer(s), and it is desired that the filmundergo further improvements in productivity and durability.

SUMMARY OF THE INVENTION

An aspect of an illustrative, non-limiting embodiment of the inventionis to provide an antireflective film that has excellent antistaticproperties aimed at preventing adhesion of dust (dirt or the like), highadhesion and high physical strength including abrasion resistance andensures excellent productivity.

Another aspect of an illustrative, non-limiting embodiment of theinvention is to provide a polarizing plate using the aforesaidantireflective film (a protective film for a polarizing plate, which hasundergone antireflective treatment according to an appropriate method)and an image display device using such a polarizing plate.

As a result of our intensive studies to solve the issues as describedabove, it has been found that the foregoing aspects can be realized bymeans described below. More specifically, aspects of the inventioninclude the following:

(1) An antireflective film including: a transparent substrate; at leastone conductive layer formed from a composition containing a transparentconductive polymeric material and a compound forming a cross-linkingsite (hereinafter referred to as a cross-linking site-forming compound)having a plurality of cross-linking reactive groups, at least one ofwhich cross-links with the transparent conductive polymeric material;and at least one low refractive index layer.

(2) The antireflective film as described in (1), further including atleast one hard coating layer and an antiglare layer between thetransparent substrate and the conductive layer.

(3) The antireflective film as described in (1) or (2), wherein thetransparent conductive polymeric material is a complex of a π-conjugatedconductive polymer and a polymer dopant.

(4) The antireflective film as described in (3), wherein the polymerdopant has at least two groups, at least one of which is an anionicgroup and at least another one of which is a non-anionic group.

(5) The antireflective film as described in (3) or (4), wherein thecross-linking site-forming compound has a group cross-linking with thepolymer dopant.

(6) The antireflective film as described in any one of (3) to (5),wherein the cross-linking site-forming compound is a compound having agroup capable of cross-linking with the polymer dopant and a grouphaving an ethylenically unsaturated double bond or an oligomer having agroup capable of cross-linking with the polymer dopant and a grouphaving an ethylenically unsaturated double bond.

(7) The antireflective film as described in any one of (3) to (6),wherein the cross-linking site-forming compound is a hydrolysate of amixture of a compound represented by formula (1) and a compoundrepresented by formula (2), and/or a condensate of the hydrolysate:(R¹)_(m)-M¹-(OR³)_(n)  (I)(where R¹ is a group having as a partial structure a group cross-linkingwith the polymer dopant, R³s are the same or different and each of themis an alkyl group or a haloalkyl group, n is 1 or above, m is 1 orabove, and M¹ is silicon, aluminum, zirconium, titanium, tin orantimony)(R²)_(p)-M²-(OR⁴)_(q)  (II)(where R² is a group having as a partial structure an ethylenicallyunsaturated double bond, R⁴s are the same or different and each of themis an alkyl group or a haloalkyl group, p is 1 or above, q is 1 orabove, and M² is silicon, aluminum, zirconium, titanium, tin orantimony).

(8) The antireflective film as described in any one of (1) to (7),including on the conductive layer a middle refractive index layer with arefractive index of 1.5 to 1.7, a high refractive index layer with arefractive index of 1.7 to 2.1 and the low refractive index layer with arefractive index of 1.3 to 1.5 in increasing order of distance from thetransparent substrate.

(9) A polarizing plate including a polarizer sandwiched between twoprotective films, at least one of which is the antireflective film asdescribed in any one of (1) to (8).

(10) An image display device including the polarizing plate as describedin (9).

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

According to an aspect of the invention, it is possible to produce anantireflective film which has excellent antistatic properties, highadhesion and high abrasion resistance and ensures high productivity.Display devices (image display devices) provided with the presentantireflective films or the present polarizing plates are reduced inextraneous light reflected off and background's reflection mirrored intheir respective screens, so very high visibility forms a feature ofthem.

An antireflective film according to an aspect of the invention isillustrated below.

<Layer Structure of Antireflective Film>

An antireflective film according to an aspect of the invention has on atransparent substrate (which is also referred to as a transparentsupport, a base film or a support) at least one conductive layer and atleast one low refractive index layer, and can further have otherfunctional layers singly or in the form of multiple layers in accordancewith the intended use thereof.

One among preferred embodiments of the present antireflective film is amultilayer antireflective film formed by providing constituent layers ona substrate so as to achieve reflectivity reduction by opticalinterference in consideration of their refractive indexes, layerthicknesses, number and arranging order. The most simple structure of anantireflective film is a structure that only a low refractive indexlayer is applied to a substrate. For further reduction in reflectivity,it is favorable to configure an antireflective layer as a combination ofa high refractive index layer having a higher refractive index than asubstrate and a low refractive index layer having a lower refractiveindex than a substrate. Examples of a layer structure of theantireflective layer include a double-layer structure that a substrateis coated with a high refractive index layer and a low refractive indexlayer in order of mention and a triple-layer structure that a substrateis coated with three layers different in refractive index, namely amiddle refractive index layer (which has a refractive index higher thanthe substrate or a hard coating layer and lower than a high refractiveindex layer), a high refractive index layer and a low refractive indexlayer which are stacked on top of each other in order of mention. Inaddition, there are many proposals of an antireflective film having astack of more antireflective layers. Of those proposals, a structurethat a middle refractive index layer, a high refractive index layer anda low refractive index layer are applied in order of mention to a hardcoating layer provided on a substrate is preferred from the viewpointsof durability, optical properties, cost and productivity. Examples ofsuch a structure include those disclosed in JP-A-8-122504,JP-A-8-110401, JP-A-10-300902, JP-A-2002-243906 and JP-A-2000-111706.

Moreover, another function may be imparted to each constituent layer.For instance, soil-resistant properties may be imparted to a lowrefractive index layer, while anti-static properties may be imparted toa high refractive index layer (as disclosed, e.g., in JP-A-10-206603 andJP-A-2002-243906).

Examples of a layer structure preferred by the present antireflectivefilm are shown below. In each of the following structures, the term“base film” refers to the support formed of a film.

-   -   Base film/conductive layer/low refractive index layer    -   Base film/hard coating layer/conductive layer/low refractive        index layer    -   Base film/antiglare layer/conductive layer/low refractive index        layer    -   Base film/conductive layer/hard coating layer/low refractive        index layer    -   Base film/conductive layer/antiglare layer/low refractive index        layer    -   Base film/moisture-proof layer/hard coating layer/conductive        layer/low refractive index layer    -   Base film/moisture-proof layer/antiglare layer/conductive        layer/low refractive index layer    -   Moisture-proof layer/base film/hard coating layer/conductive        layer/low refractive index layer    -   Moisture-proof layer/base film/antiglare layer/conductive        layer/low refractive index layer    -   Base film/conductive layer/middle refractive index layer/high        refractive index layer/low refractive index layer    -   Base film/hard coating layer/conductive layer/medium refractive        index layer/high refractive index layer/low refractive index        layer    -   Moisture-proof layer/base film/hard coating layer/conductive        layer/middle refractive index layer/high refractive index        layer/low refractive index layer

These layers can be formed according to an evaporation method, anatmospheric pressure plasma method, a coating method or so on. In pointof productivity, formation by a coating method is advantageous.

Various layers which can constitute the present antireflective layer aredescribed below.

1. Conductive Layer

The conductive layer for use in the invention is high in conductivity,flexibility and adhesion to adjacent layers, and can be formed easily byuse of a coating method.

(1) Transparent Conductive Material

Herein, the transparent conductive material denotes a polymericsubstance having transparency and conductivity, and it is a simplematerial or a complex of two or more materials.

As the transparent conductive material, a cationic or anionic polymershowing ionic conductivity or an electronic conductivity-exhibitingcomplex of a π-conjugated conductive polymer and a dopant attendantthereto can be used to advantage. Of these two materials, the complex ofa π-conjugated conductive polymer and a dopant attendant thereto isespecially preferable to the other.

1-(1) π-Conjugated Conductive Polymer

As the π-conjugated conductive polymer, any of organic polymers havingπ-conjugated systems as their respective main chains can be used.Examples of such a polymer include polypyrrole, polythiophene,polyacetylene, polyphenylene, polyphenylenevinylene, polyaniline,polyacene, polythiophenevinylene, and a copolymer of thereof. In pointof easiness of polymerization and stability in the air, polypyrrole,polythiophene and polyaniline are preferred over the others.

Although such π-conjugated conductive polymers can have sufficientconductivity and compatibility with binder resins without having anysubstituents, introduction of functional groups, such as alkyl,carboxyl, sulfo, alkoxy, hydroxyl or cyano groups, into thoseπ-conjugated conductive polymers is favorable for further increasingdispersibility or solubility in a binder resin as well as conductivity.

As to such a π-conjugated conductive polymers, examples of such asubstituted polypyrrole include poly(3-methylpyrrole),poly(3-ethylpyrrole), poly(3-n-propylpyrrole), poly(3-butylpyrrole),poly(3-octylpyrrole), poly(3-decylpyrrole), poly(3-docecylpyrrole),poly(3,4-dimethylpyrrole), poly(3,4-dibutylpyrrole),poly(3-carboxypyrrole), poly(3-methyl-4-carboxypyrrole),poly(3-methyl-4-carboxyethylpyrrole),poly(3-methyl-4-carboxybutylpyrrole), poly(3-hydroxypyrrole),poly(3-methoxypyrrole), poly(3-ethoxypyrrole), poly(3-butoxypyrrole),poly(3-hexyloxypyrrole) and poly(3-methyl-4-hexyloxypyrrole).

Examples of polythiophene include poly(3-methylthiophene),poly(3-ethylthiophene), poly(3-propylthiophene), poly(3-butylthiophene),poly(3-hexylthiophene), poly(3-heptylthiophene), poly(3-octylthiophene),poly(3-decylthiophene), poly(3-dodecylthiophene),poly(3-octadecylthiophene), poly(3-bromothiophene),poly(3-chlorothiophene), poly(3-iodothiophene), poly(3-cyanothiophene),poly(3-phenylthiophene), poly(3,4-dimethylthiophene),poly(3,4-dibutylthiophene), poly(3-hydroxythiophene),poly(3-methoxythiophene), poly(3-ethoxythiophene),poly(3-butoxythiophene), poly(3-hexyloxythiophene),poly(3-heptyloxythiophene), poly(3-octyloxythiophene)poly(3-decyloxythiophene), poly(3-dodecyloxythiophene),poly(3-octadecyloxythiophene), poly(3,4-dihydroxythiophene),poly(3,4-dimethoxythiophene), poly(3,4-diethoxythiophene),poly(3,4-dipropoxythiophene), poly(3,4-dibutoxythiophene),poly(3,4-dihexyloxythiophene), poly(3,4-diheptyloxythiophene),poly(3,4-dioctyloxythiophene), poly(3,4-didecyloxythiophene),poly(3,4-didodecyloxythiophene), poly(3,4-ethylenedioxythiophene),poly(3,4-propylenedioxythiophene), poly(3,4-butenedioxythiophene),poly(3-methyl-4-methoxythiophene), poly(3-methyl-4-ethoxythiophene),poly(3-carboxythiophene), poly(3-methyl-4-carboxythiophene),poly(3-methyl-4-carboxyethylthiophene) andpoly(3-methyl-4-carboxybutylthiophene).

Examples of polyaniline include poly(2-methylaniline),poly(3-isobutylaniline), poly(2-anilinesulfonic acid) andpoly(3-anilinesulfonic acid).

Of those polymers, a homopolymer selected from polypyrrole,polythiophene, poly(N-methylpyrrole), poly(3-methylthiophene),poly(3-methoxythiophene) or poly(3,4-ethylenedioxythiophene), or acopolymer of any two of constituent monomers of the polymers recitedabove is preferably used in point of resistance and reactivity.Furthermore, polypyrrole and poly(3,4-ethylenedioxythiophene) have anadvantage over the others in that they have higher conductivity andyield an improvement in heat resistance.

In addition, the polymers substituted by alkyl groups, such aspoly(N-methylpyrrole) and poly(3-methylthiophene), are also advantageousbecause they obtain improvements in solvent solubility and compatibilitywith and dispersibility in a binder resin. Of the alkyl groups, a methylgroup is preferred over the others because it has no negative effect onthe conductivity.

1-(2) Dopant

The transparent conductive material is preferably a complex of theπ-conjugated conductive polymer as recited above and a dopant.

The dopant is preferably a polymer dopant, notably a polyanionic polymerthat has anionic groups in a molecule.

The dopant including a polyanionic polymer is hereinafter referred to asa polyanionic dopant. The complex formation is effected via saltformation by chemically oxidative doping of a conductive polymer withsuch a polyanionic dopant.

The anionic groups of a polyanionic dopant are preferably functionalgroups which enable chemically oxidative doping of a conductive polymerwith the dopant, and besides, proton acids of which can unite with anyof vinyl, glycidyl and hydroxyl groups. Suitable examples of such protonacids include a sulfuric acid group, a phosphoric acid group, a sulfogroup, a carboxyl group and a phospho group. Of these acid groups, asulfo group and a carboxyl group are preferred over the others from theviewpoint of chemically oxidative doping.

Examples of a polyanionic dopant having sulfo groups include avinylsulfonic acid polymer, a styrenesulfonic acid polymer, anallylsulfonic acid polymer, an acrylsulfonic acid polymer, amethacrylsulfonic acid polymer, a 2-acrylamide-2-methylpropanesulfonicacid polymer and an isoprenesulfonic acid polymer. Each of thesepolymers may be a homopolymer or a copolymer of its constituent monomerand any one or more of constituent monomers of the other polymers.

Examples of a polyanionic dopant having carboxyl groups include avinylcarboxylic acid polymer, a styrenecarboxylic acid polymer, anallylcarboxylic acid polymer, an acrylcarboxylic acid polymer, amethacrylcarboxylic acid polymer, a2-acrylamide-2-methylpropanecarboxylic acid polymer, anisoprenecarboxylic acid polymer and an acrylic acid polymer. Each ofthese polymers may be a homopolymer or a copolymer of its constituentmonomer and any one or more of constituent monomers of the otherpolymers.

The transparent conductive material can be produced with ease byperforming, in a solvent, chemical oxidation polymerization of aprecursor monomer to form the π-conjugated conductive polymer in thepresence of an appropriate oxidant, an appropriate oxidation catalystand the polymer dopant as recited above (preferably a polyanionicdopant).

The conductive material may contain a dopant other than the polyanionicdopant as recited above in order to have further enhanced electricconductivity and thermal stability. Examples of such a dopant includehalogen compounds, Lewis acids and proton acids. More specifically, theyinclude organic acids such as an organic carboxylic acid and organicsulfonic acid, organic cyano compounds and fullerene compounds.

As to the halogen compounds, examples thereof include chlorine, bromine,iodine, iodine chloride, iodine bromide and iodine fluoride.

As to the proton acids, examples thereof include inorganic acids, suchas hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid,fluoroboric acid, hydrofluoric acid and perchloric acid, organiccarboxylic acids, phenolic compounds and organic sulfonic acids.

As to the organic carboxylic acids, examples thereof include formicacid, acetic acid, oxalic acid, benzoic acid, phthalic acid, maleicacid, fumaric acid, malonic acid, tartaric acid, citric acid, lacticacid, succinic acid, monochloroacetic acid, dichloroacetic acid,trichloroacetic acid, trifluoroacetic acid, nitroacetic acid andtriphenylacetic acid.

As to the organic sulfonic acids, examples thereof includealkylbenzenesulfonic acids, alkylnaphthalenesulfonic acids,alkylnaphthalenedisulfonic acids, polycondensation products ofnaphthalenesulfonic acid and formaldehyde, polycondensation products ofmelaminesulfonic acid and formaldehyde, naphthalenedisulfonic acid,naphthalenetrisulfonic acid, dinaphthylmethanedisulfonic acid,anthraquinonesulfonic acid, anthraquinonedisulfonic acid,anthracenesulfonic acid and pyrenesulfonic acid. In addition, metalsalts of these acids can also be used.

As to the organic cyano compounds, examples thereof includedichlorodicyanobenzoquinone (DDQ), tetracyanoquinodimethane andtetracyanoazanaphthalene.

As to the fullerene compounds, examples thereof include hydrogenatedfullerene, hydroxylated fullerene, carboxylated fullerene and sulfonatedfullerene.

It is preferable that a polymer dopant is cross-linked with any of thecross-linking site-forming compounds described hereinafter. Theformation of cross-links can enhance the adhesion of the conductivelayer and ensure excellent abrasion resistance.

Additionally, it is also preferable that the polymer dopant has at leasttwo kinds of functional groups, at least one kind of which are anionicgroups and at least another kind of which are non-anionic groups.

Among the functional groups that the polymer dopant has, anionic groupsremaining without forming salts together with the π-conjugatedconductive polymer as recited above or the non-anionic groups arepreferably cross-linked with the cross-linking site-forming compound asdescribed hereinafter.

The non-anionic functional groups of the polymer dopant have noparticular restrictions so long as they can be cross-linked with thecross-linking site-forming compounds as described below, but hydroxyl,amino and mercapto groups can be given as examples thereof. These groupseach can be introduced into the polymer dopant by copolymerizing aconstituent monomer of the polymer dopant and a monomer chosenappropriately from 2-vinylethanol, hydroxymethyl vinyl ketone,2-hydroxyethyl vinyl ketone, allylamine, 2-aminoethyl vinyl ether,3-vinyloxy-1-propylamine or 2-allylaminoethanethiol. The proportion ofmonomeric units having non-anionic functional groups in the copolymer ispreferably from 1 to 50 mole %, particularly preferably from 5 to 30mole %. When the proportion is lower than 1 mole %, the cross-linkingsites becomes deficient in number; while, when the proportion is higherthan 50 mole %, the resultant copolymer cannot function sufficiently asanionic dopant.

1-(3) Complex of π-Conjugated Conductive Polymer and Polymer Dopant

Taking the case of a polyanionic dopant, the complex of a π-conjugatedconductive polymer and a polymer dopant is illustrated below.

During the complex formation, as the main chain of a conductive polymergrows, so are salts formed between anionic groups of a polyanionicdopant and the conductive polymer. Accordingly, the main chain of theconductive polymer grows along the polyanionic dopant and countlesssalts are formed between the resultant conductive polymer and thepolyanionic dopant, thereby producing a complex. In this complex, it ispresumed that every three monomeric units of the conductive polymer andevery one anionic-group unit form a salt and several pieces ofshort-grown polymer form salts along the polyanionic dopant with a longlength.

One example of a method of forming a complex that combines a conductivepolymer and a polyanionic dopant is a method of performing chemicaloxidation polymerization of a monomer to form the conductive polymer inthe presence of the polyanionic dopant.

In the chemical oxidation polymerization, the oxidant and the oxidationcatalyst used for polymerizing the monomer are not particularlyrestricted so long as they can oxidize the precursor monomer andcontribute to production of the π-conjugated conductive polymer, andexamples thereof include peroxosulfates, such as ammoniumperoxodisulfate, sodium peroxodisulfate and potassium peroxodisulfate;transition metal compounds, such as ferric chloride, ferric sulfate,ferric nitrate and cupric chloride; metal halides, such as borontrifluoride and aluminum chloride; metal oxides, such as silver oxideand cesium oxide; peroxides, such as hydrogen peroxide and ozone;organic peroxides, such as benzoyl peroxide; and oxygen.

The chemical oxidation polymerization may be carried out in a solvent.The solvent used therein has no particular restriction so long as it candissolve the polyanionic dopant used and the conductive polymer formedtherein. Examples of such a solvent include water, methanol, ethanol,propylene carbonate, cresol, phenol, xylenol, acetone, methyl ethylketone, hexane, benzene, toluene, dioxane, diethyl ether, acetonitrile,benzonitrile, N,N-dimethylformamide, N,N-dimethylacetamide,N-methyl-2-pyrrolidone, hexamethylphosphoric triamide,1,3-dimethyl-2-imidazolidine, dimethylimidazoline, ethyl acetate,2-methyltetrahydrofuran, dimethylsulfoxide, sulfolane anddiphenylsulfone. These solvents can be used alone or as mixed solvent ofany two or more thereof on an as needed basis.

The amount of a transparent conductive material applied is preferablyfrom 0.01 to 5.0 g/m², far preferably from 0.05 to 2.0 g/m², especiallypreferably from 0.10 to 1.0 g/m².

When the transparent conductive material is the complex of aπ-conjugated conductive polymer and a polymer dopant, the ratio of theper-unit molecular weight of the π-conjugated conductive polymer to theper-unit molecular weight of the polymer dopant is preferably from 1:1to 1:5, far preferably from 1:1 to 1:2.

1-(4) Cross-Linking Site-Forming Compound

The term “cross-linking site-forming compound” as used in the inventionrefers to a compound having a plurality of cross-linking reactivegroups, at least one of which cross-links with a transparent conductivematerial.

When the transparent conductive material is the complex of aπ-conjugated conductive polymer and a polymer dopant, it is preferablethat the cross-linking site-forming compound cross-links with thepolymer dopant, especially residual anionic groups and/or non-anionicfunctional groups of the polymer dopant.

The group that is present in the cross-linking site-forming compound andcross-links with an anionic group or non-anionic group in the polymerdopant is preferably a hydroxyl group, an alkoxysilyl group, a cyclicether group or an isocyanate group, far preferably a group having as apartial structure a glycidyl group, an oxetane group or an isocyanategroup, most preferably an isocyanate group.

In an exemplary embodiment of the invention, cross-liking is performedsuch that a residual anionic group (e.g., a sulfo group or a carboxylgroup) of polyanion of the polymer dopant reacts with a hydroxyl group,an alkoxysilyl group or a cyclic ether group of the cross-linkingsite-forming compound to form an ester. In another exemplary embodimentof the invention, cross-liking is performed such that a non-anionicfunctional group (e.g., a hydroxyl group or an amino group) of thepolymer dopant reacts with a cyclic ether group or an isocyanate groupof the cross-linking site-forming compound.

In order to cause these reactive groups to react effectively, variouscatalysts and various polymerization initiators may be used.

For the cyclic ether group, a catalyst such as a tertiary amine or aquaternary ammonium salt, and a cationic photo-initiator such as aniodonium salt or a sulfonium salt may be used.

For the isocyanate group, a catalyst such as a tertiary amine or anorganometallic compound may be used.

It is a preferred embodiment of the invention that the cross-linkingsite-forming compound has a group that can cross-link with a polymerdopant and a reactive group other than groups capable of cross-linkingwith a polymer dopant. The reactive group other than groups capable ofcross-linking with a polymer dopant is preferably a group having anethylenically unsaturated double bond, and more specifically, a grouphaving as a partial structure a (meth)acryloyl group, an allyl group, avinyl ether group or a (meth)acrylamide group.

In order to cause these reactive groups to react effectively, variouscatalysts and various polymerization initiators may be used, and the useof various radical photo-initiators in particular is favorable.

Cross-linking site-forming compounds usable in the invention are notlimited to particular ones, but suitable examples thereof include thecompounds illustrated below.

It is another preferred embodiment of the invention that thecross-linking site-forming compound is an oligomer having groups capableof cross-linking with a polymer dorpant and groups having ethylenicallyunsaturated double bonds. The groups capable of cross-linking with apolymer dopant and the groups having ethylenically unsaturated doublebonds are the same as recited above.

The mass-average molecular weight of the oligomer having groups capableof cross-linking with a polymer dopant and groups having ethylenicallyunsaturated double bonds is preferably from 500 to 10,000, farpreferably from 500 to 5,000, especially preferably from 700 to 3,000,as determined in a condition that components having molecular weightbelow 300 are excluded.

As to the oligomer having groups capable of cross-linking with a polymerdopant and groups having ethylenically unsaturated double bonds, it isappropriate that the components having molecular weight greater than10,000 make up 10 mass % (weight %) or below, preferably 5 mass % orbelow, far preferably 3 mass % or below, of the total components havingmolecular weight of 300 or above. When the oligomer including suchcomponents in a content greater than 10 mass % is used in a (curable)composition, it sometimes occurs that the cured film obtained by curingthe resultant composition is inferior in transparency and adhesion to asubstrate.

Herein, the mass-average molecular weight and the molecular weight aremolecular weight values measured with a GPC analyzer using columns,TSKgel GMHxL, TSKgel G4000HxL and TSKgel G2000HxL (which are all thetrade names of products of Tosoh Corporation), and THF as a solvent andcalculated in terms of polystyrene according to detection by adifferential refractometer, and the content is shown as a percentage ofthe total area of peaks in the foregoing molecular weight range, withthe total area of peaks corresponding to molecular weight of 300 orabove being taken as 100%.

Moreover, it is preferable that the cross-linking site-forming compoundis hydrolysate of at least one mixture of a compound represented by thefollowing formula (1) and a compound represented by the followingformula (2), and/or condensate of the hydrolysate.(R¹)_(m)-M¹-(OR³)_(n)  Formula (1)

Herein, R¹ is a group having as a partial structure a group capable ofcross-linking with the polymer dopant as recited above, R³s are the sameor different and each of them is an alkyl group or a haloalkyl group, nis 1 or above, m is 1 or above, and M¹ is silicon, aluminum, zirconium,titanium, tin or antimony.

R¹ is a group capable of cross-linking with the polymer dopant asrecited above, preferably a cyclic ether group or an isocyanate group,far preferably a group having as a partial structure a glycidyl group,an oxetane group or an isocyanate group.

R³ is preferably an alkyl group, notably an ethyl group or a methylgroup.

m is preferably 1, and n is preferably 2 or above.

As to M¹, silicon in particular is preferred over the others.(R²)_(p)-M²-(OR⁴)_(q)  Formula (2)

Herein, R² is a group having as a partial structure an ethylenicallyunsaturated double bond, R⁴s are the same or different and each of themis an alkyl group or a haloalkyl group, p is 1 or above, q is 1 orabove, and M² is silicon, aluminum, zirconium, titanium, tin orantimony.

R² is a group having an ethylenically unsaturated double bond,preferably a group having as a partial structure a (meth)acryl group, anallyl group, a vinyl ether group or a (meth)acrylamide group.

R⁴ is preferably an alkyl group, notably an ethyl group or a methylgroup.

p is preferably 1, and q is preferably 2 or above.

As to M², silicon in particular is preferred over the others.

Hydrolysate of at least one mixture of a compound represented by formula(1) and a compound represented by formula (2), and/or condensate of thehydrolysate is a cross-linking site-forming compound in a sol state.This compound is combined with a polymer dorpant at two or more of itscross-linking sites, and the components thereof further form bonds amongthemselves at their residual cross-linking sites. So, an increase incross-linking density of the conductive layer can be achieved.

Examples of a compound represented by formula (1), though notparticularly restricted, include the following.

Examples of a compound represented by formula (2), though notparticularly restricted, include the following.

As to at least one mixture of a compound represented by formula (1) anda compound represented by formula (2), the ratio of the compoundrepresented by formula (1) to the compound represented by formula (2) ispreferably from 1:9 to 9:1 by mole, far preferably from 2:8 to 8:2 bymole, particularly preferably from 3:7 to 7:3 by mole.

The hydrolysis and condensation reactions are performed by adding waterin an amount of 0.05 to 2.0 moles, preferably 0.1 to 1.0 mole, per moleof hydrolyzable groups (OR³ and OR⁴ in formulae (1) and (2)) andstirring at a temperature between 25° C. and 100° C. in the presence ofa catalyst usable in the invention.

The mass-average molecular weight of the hydrolysate and partialcondensate thereof is preferably from 500 to 10,000, far preferably from500 to 5,000, especially preferably from 700 to 3,000, as determined ina condition that components having molecular weight below 300 areexcluded.

Of the components having molecular weight of 300 or above in thehydrolysate and its partial condensate, the components having molecularweight greater than 10,000 make up preferably 10 mass % or below, farpreferably 5 mass % or below, further preferably 3 mass % or below. Whensuch high molecular-weight components have a content greater than 10mass %, it sometimes occurs that the cured film obtained by curing thecurable composition containing such hydrolysate and its partialcondensate is inferior in transparency and adhesion to a substrate.

Herein, the mass-average molecular weight and the molecular weight aremolecular weight values measured with a GPC analyzer using columns,TSKgel GMHxL, TSKgel G4000HxL and TSKgel G2000HxL (which are all thetrade names of products of Tosoh Corporation), and THF as a solvent andcalculated in terms of polystyrene according to detection by adifferential refractometer, and the content is shown as a percentage ofthe total area of peaks in the foregoing molecular weight range, withthe total area of peaks corresponding to molecular weight of 300 orabove being taken as 100%.

By ²⁹Si—NMR analyses of the hydrolysate and its partial condensate, thestate in which the hydrolyzable groups in formulae (1) and (2) arecondensed into —OSi forms can be ascertained.

Herein, when the occurrence of a case where three bonds of Si undergocondensation into the form of —OSi is denoted by T3, the occurrence of acase where two bonds of Si undergo condensation into the form of —OSi isdenoted by T2, the occurrence of a case where one bond of Si undergoescondensation into the form of —OSi is denoted by T1 and the occurrenceof a case where no bond of Si undergoes condensation is denoted by T0,the condensation rate a is determined by the expressionα=(T3×3+T2×2+T1×1)/3/(T3+T2+T1+T0). And the condensation rate ispreferably from 0.2 to 0.95, far preferably from 0.3 to 0.93,particularly preferably from 0.4 to 0.9.

The a value smaller than 0.1 means that hydrolysis and condensation areinsufficient, so such a case cannot offer sufficient curing because themonomer content is high, while the a value greater than 0.95 means thathydrolysis and condensation advance to excess and most of hydrolyzablegroups are consumed, so such a case resists producing the intendedeffects because it causes reductions in interactions with a binderpolymer, a resin substrate and inorganic fine particles.

The hydrolysate and its partial condensate are described in more detail.The hydrolysis reaction and the condensation reaction subsequent theretoare generally carried out in the presence of a catalyst. Examples ofsuch a catalyst include inorganic acids, such as hydrochloric acid,sulfuric acid and nitric acid; organic acids, such as oxalic acid,acetic acid, butyric acid, maleic acid, citric acid, formic acid,methanesulfonic acid and toluenesulfonic acid; inorganic bases, such assodium hydroxide, potassium hydroxide and ammonia; organic bases, suchas triethylamine and pyridine; metal alkoxides, such astriisopropoxylaluminum, tetrabutoxyzirconium, tetrabutyltitanate anddibutyltin dilaurate; metal chelate compounds having as their individualcentral metal Zr, Ti or Al or the like; and fluorine-containingcompounds, such as KF and NH₄F.

These catalysts may be use alone or as combinations of two or morethereof.

The hydrolysis and condensation reactions can be performed in asolventless or in-solvent condition, but it is preferable to use anorganic solvent for homogeneous mixing of ingredients. Examples of anorganic solvent suitable for such a purpose include alcohol, aromatichydrocarbon, ether, ketone and ester.

The solvents preferred herein are solvents in which compoundsrepresented by formula (1) and/or compounds represented by formula (2)and catalysts can be dissolved. In addition, it is preferable that suchsolvents are organic solvents which provide advantages in processes whenused as coating solutions or part of coating solutions, and what's morewhich are not detrimental to solubility and dispersiblity when mixedwith other ingredients including fluoropolymers.

Alcohol usable for the foregoing purpose includes monohydric alcohol anddihydric alcohol. As the monohydric alcohol, 1-8C saturated aliphaticalcohol compounds are suitable.

Examples of the alcohol include methanol, ethanol, n-propyl alcohol,i-propyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butylalcohol, ethylene glycol, diethylene glycol, triethylene glycol,ethylene glycol monobutyl ether and ethylene glycol acetate monoethylether.

Examples of the aromatic hydrocarbon include benzene, toluene andxylene, examples of the ether include tetrahydrofuran and dioxane,examples of the ketone include acetone, methyl ethyl ketone, methylisobutyl ketone, diisobutyl ketone and cyclohexanone, and examples ofthe ester include ethyl acetate, propyl acetate, butyl acetate andpropylene carboxylate.

The organic solvents as recited above can be used alone or as mixturesof two or more thereof. In those reactions, the solids concentration hasno particular limitation, but it is generally in the 1%-to-100% range.

Those reactions are performed through addition of water in an amount of0.05 to 0.2, preferably 0.1 to 1 mole per mole of hydrolyzable groups incompounds of formulae (1) and (2) and agitation with or without asolvent in the presence of a catalyst at a temperature between 25° C. to100° C.

In the invention, it is preferable that the hydrolysis is carried outthrough agitation at a temperature between 25° C. and 100° C. in thepresence of at least one metal-chelate compound that has ligandsincluding alcohol represented by formula R⁵OH (wherein R⁵ represents a1-10C alkyl group) and a compound represented by formula R⁶COCH₂COR⁷(wherein R⁶ represents a 1-10C alkyl group and R⁷ represents a 1-10Calkyl group or a 1-10C alkoxy group) and contains as its central metal ametal chosen from Zr, Ti or Al.

Alternatively, it is advantageous to use a fluorine-containing compoundas a catalyst. This is because fluorine-containing compounds have anability to advance hydrolysis and condensation completely, so they candetermine the degree of polymerization through selection of additionamount of water and therefore permit arbitrary setting of molecularweight.

As far as the metal-chelate compound has ligands including alcoholrepresented by formula R⁵OH (wherein R⁵ represents a 1-10C alkyl group)and a compound represented by formula R⁶COCH₂COR⁷ (wherein R⁶ representsa 1-10C alkyl group and R⁷ represents a 1-10C alkyl group or a 1-10Calkoxy group) and contains as its central metal a metal chosen from Zr,Ti or Al, it can be favorably used without any other particularrestriction. Two or more metal-chelate compounds may be used incombination so long as they fall under the category defined above. Morespecifically, the metal-chelate compound favorably used in the inventionis a compound selected from among the compounds represented by formulaeZr(OR⁵)_(p1)(R⁶COCHCOR⁷)_(p2), Ti(OR⁵)_(q1)(R⁶COCHCOR⁷)_(q2) andAl(OR⁵)_(r1)(R⁶COCHCOR⁷)_(r2), respectively, and serves a function ofpromoting condensation reaction of hydrolysate and its partialcondensate.

The 1-10C alkyl groups represented by R⁵s or R⁶s in each of themetal-chelate compounds may be the same or different, and examplesthereof include an ethyl group, an n-propyl group, an i-propyl group, ann-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group anda phenyl group. Examples of R⁷ include not only the 1-10C alkyl groupsas recited above but also 1-10C alkoxy groups, such as a methoxy group,an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxygroup, a sec-butoxy group and a t-butoxy group. In addition, p1, p2, q1,q2, r1 and r2 in the metal-chelate compounds represent integersdetermined so as to satisfy the equations p1+p2=4, q1+q2=4 and r1+r2=3.

Examples of those metal-chelate compounds are not limited to particularones, but they include zirconium-chelate compounds, such as zirconiumtri-n-butoxyethylacetoacetate, zirconiumdi-n-butoxybis(ethylacetoacetate), zirconiumn-butoxytris(ethylacetoacetate), zirconiumtetrakis(n-propylacetoacetate), zirconium tetrakis(acetylacetoacetate)and zirconium tetrakis(ethylacetoacetate); titanium-chelate compounds,such as titanium diisopropoxybis(ethylacetoacetate), titaniumdiisopropoxybis(acetylacetate) and titaniumdiisopropoxybis(acetylacetone); and aluminum-chelate compounds, such asaluminum diisopropoxyethylacetoacetate, aluminumdiisopropoxyacetylacetonate, aluminum isopropoxybis(ethylacetoacetate),aluminum isopropoxybis(acetylacetonate), aluminumtris(ethylacetoacetate), aluminum tris(acetylacetonate) and aluminummonoacetylacetonatebis(ethylacetoacetate).

Preferred ones of the metal-chelate compounds recited above arezirconium tri-n-butoxyethylacetoacetate, titaniumdiisopropoxybis(acetylacetonate), aluminum diisopropoxyethylacetoacetateand aluminum tris(ethylacetoacetate). Those metal-chelate compounds maybe used alone or as mixtures of two or more thereof. Moreover, partialhydrolysis products of those metal-chelate compounds can also be used.

The proportion in which the metal-chelate compound or compounds are usedon the compounds of formulae (1) and (2) is preferably from 0.01 to 50mass %, far preferably from 0.1 to 50 mass %, further preferably from0.5 to 10 mass %. By using the metal-chelate compound or compounds inthe proportion range as specified above, rapid progress of condensationreaction becomes possible, the coating film formed can have gooddurability, and the composition containing the hydrolysate, the partialcondensate and the metal-chelate compound(s) in accordance with theinvention becomes satisfactory in storage stability.

To the coating solution used in the invention, at least either aβ-diketone compound or a β-ketoester compound is preferably added inaddition to the composition containing the sol component and themetal-chelate compound(s). Further description of this addition is givenbelow.

The compound preferably added is at least either a β-diketone orβ-ketoester compound represented by formula R⁶COCH₂COR⁷, and itfunctions as a stability improver for the composition used in theinvention. More specifically, it is thought that the β-diketone orβ-ketoester compound added and the metal atom(s) in the metal-chelatecompound(s) (at least any of the zirconium, titanium and aluminumcompounds) are coordinated, and thereby the function of themetal-chelate compounds, namely promotion of the condensation reactionof hydrolysate and partial condensate of the compounds represented byformulae (1) and (2), is inhibited, and the storage stability of theresultant composition is enhanced. R⁶ and R⁷ constituting each of theβ-diketone and β-ketoester compounds have the same meanings as thoseconstituting the metal-chelate compound as recited above, respectively.

Examples of such β-diketone and β-ketoester compounds includeacetylacetone, methyl acetoacetate, ethyl acetoacetate, n-propylacetoacetate, i-propyl acetoacetate, n-butyl acetoacetate, sec-butylacetoacetate, t-butyl acetoacetate, 2,4-hexanedione, 2,4-heptanedione,3,5-heptanedione, 2,4-octanedione, 2,4-nonanedione and5-methyl-hexanedione. Of these compounds, ethyl acetoacetate andacetylacetone are preferred over the others, and acetylacetone inparticular is used to advantage. These β-diketone and β-ketoestercompounds can be used alone or as mixtures of two or more thereof. Inthe invention, it is appropriate that the β-diketone or β-ketoestercompound be used in an amount of 2 moles or above, preferably 3 to 20moles, per mole of the metal-chelate compound(s). The addition in anamount smaller than 2 mole is undesirable because there is a fear forpoor storage stability of the resultant composition.

The amount of the cross-linking site-forming compound applied ispreferably from 0.01 to 3.0 g/m², far preferably from 0.02 to 2.0 g/m²,especially preferably from 0.05 to 1.0 g/m².

The conductive layer in the invention can be formed with ease inaccordance with such a coating method as described below. The thicknessof the conductive layer is preferably from 0.01 to 10 μm, far preferablyfrom 0.03 to 7 μm, further preferably 0.05 to 5 μm.

In addition, the surface resistance of the conductive layer ispreferably from 10⁴ to 10¹³ Ω/sq, far preferably from 10⁵ to 10¹² Ω/sq,especially preferably from 10⁶ to 10¹¹ Ω/sq. The surface resistance ofthe conductive layer can be determined by a four-probe method.

The conductive layer is preferably transparent in a substantial sense.Specifically, it is preferable that the haze of the conductive layer is10% or below, preferably 5% or below, far preferably 3% or below,especially preferably 1% or below. And it is advantageous for theconductive layer to have a transmittance of light with a wavelength of550 nm in a range of 50% or above, preferably 70% or above, especiallypreferably 80% or above.

Moreover, the refractive index of the conductive layer is preferablyfrom 1.40 to 1.70, far preferably from 1.45 to 1.60.

The strength of the conductive layer according to the invention ispreferably H or higher, far preferably 2H or higher, further preferably3H or higher, especially preferably 4H or higher, expressed in terms ofthe pencil hardness under a 1-kg load.

From the viewpoint of improvement of adhesion properties of anantireflective film, it is preferred that at least one hard coatinglayer or antiglare layer as described below is provided between thetransparent substrate and the conductive layer. The adhesion propertiesbetween the transparent substrate and the conductive layer can beimproved to a certain level by including the cross-linking site-formingcompound in the conductive layer-forming composition including thepolymeric material, and can be further improved by using across-linkable or polymerizable compound in the hard coating layer orantiglare layer.

2. Hard Coating Layer

It is possible to provide the present antireflective film with a hardcoating layer, preferably on one side of the transparent substrate, forthe purpose of imparting physical strength to the film. The hard coatinglayer may have a multilayer structure including two or more layers.

From the viewpoint of an optical design for an antireflective film, itis appropriate that the refractive index of the hard coating layerprovided in the invention be in a range of 1.48 to 2.00, preferably 1.52to 1.90, far preferably 1.55 to 1.80. In a preferred embodiment of theinvention where at least one low refractive index layer is provided onthe hard coating layer, refractive indexes too lower than the range asspecified above become a cause of degradation in antireflectiveproperty, while too high refractive indexes contribute to a tendency tointensify the tint of reflected light.

From the viewpoint of imparting sufficient durability and impactresistance to the film, the thickness of the hard coating layer isadjusted generally to the order of 0.5 to 50 μm, preferably 1 to 20 μm,far preferably 2 to 10 μm, especially preferably 3 to 7 μm.

In addition, the strength of the hard coating layer is preferably H orhigher, far preferably 2H or higher, especially preferably 3H or higher,as determined by pencil hardness testing.

Furthermore, the slighter the abrasion a sample piece of hard coatinglayer suffers in the Taber test according to JIS K5400, the highersuitability the hard coating layer has.

The hard coating layer is preferably formed by cross-linking reaction orpolymerization reaction of an ionizing radiation curable compound. Morespecifically, the hard coating layer can be formed by applying a coatingcomposition containing an ionizing radiation curable multifunctionalmonomer or oligomer to the transparent substrate directly or via anotherlayer, and then by subjecting the multifunctional monomer or oligomer tocross-linking reaction or polymerization reaction.

The functional groups of the ionizing radiation curable multifunctionalmonomer or oligomer are preferably photo-, electron beam- orradiation-polymerizable functional groups. Of these groups,photopolymerizable functional groups are preferred over the others.

Examples of a photopolymerizable functional group include polymerizableunsaturated functional groups, such as a (meth)acryloyl group, a vinylgroup, a styryl group and an allyl group. Of these groups, a(meth)acryloyl group is preferred over the others.

Instead of or in addition to the polymerizable unsaturated group asrecited above, cross-linkable functional groups may be introduced intothe binder. Examples of a cross-linkable functional group include anisocyanate group, an epoxy group, an aziridine group, an oxazolinegroup, an aldehyde group, a carbonyl group, a hydrazine group, acarboxyl group, a methylol group and an active methylene group.Additionally, vinylsulfonic acid, an acid anhydride, a cyanoacrylatederivative, melamine, etherified methylol, ester, urethane and a metalalkoxide such as tetramethoxysilane can also be utilized as a monomercapable of forming a cross-linked structure. Moreover, functional groupsthat can deliver cross-linking properties as a result of decompositionreaction, such as blocked isocyanate groups, may be used. In otherwords, cross-linkable groups adopted in the invention may be groupswhose reactivity, though not shown immediately, is shown as a result ofdecomposition. The binder having such cross-linkable functional groupscan form a cross-linked structure by heating after application.

In the hard coating layer, matting particles having an average size of1.0 to 15.0 μm, preferably 1.5 to 10.0 μm, such as particles of aninorganic compound or resin particles, may be incorporated for thepurpose of imparting internal scattering properties.

To the binder of the hard coating layer, a high refractive indexmonomer, inorganic particles or both can be added for the purpose ofcontrolling the refractive index of the hard coating layer. Inorganicparticles have not only a refractive index control effect but also aneffect of inhibiting curing shrinkage from occurring by cross-linkingreaction. In the invention, the polymer produced by polymerizing any ofthe multifunctional monomers recited above, any of the high refractiveindex monomers recited above or both after formation of the hard coatinglayer, inclusive of inorganic particles dispersed therein, is referredto as the binder.

The hard coating layer is adjusted in haze to suit the function intendedto be imparted to the antireflective film.

In the case of keeping the image sharpness, reducing the surfacereflectance, and imparting a light scattering function to neither theinterior nor the surface of the hard coating layer, the lower haze valuethe better. Specifically, the haze value is preferably 10% or below, farpreferably 5% or below, especially preferably 2% or below.

On the other hand, in the case of imparting an antiglare function bysurface scattering of the hard coating layer, the surface haze ispreferably from 5% to 15%, far preferably from 5% to 10%.

In the other case of intending to render patterns, unevenness of color,inconsistency in brightness, and glare of a liquid crystal panelindistinct by internal scattering of the hard coating layer, and toimpart a function of increasing a viewing angle by scattering, theinternal haze value (the value obtained by subtracting the surface hazevalue from the total haze value) is preferably from 10% to 90%, farpreferably from 15% to 80%, especially preferably from 20% to 70%.

The present film can be adjusted to have any values of surface haze andinternal haze according to the intended purpose.

As to the surface roughness profile of the hard coating layer, it isappropriate for obtaining a clear surface with the intention of keepingimage sharpness that the center-line-average surface roughness (Ra)among the surface roughness characteristics be adjusted to 0.10 μm orbelow. The Ra value is preferably 0.08 μm or below, far preferably 0.06μm or below. In the present film, the surface roughness of the film isdominated by the surface roughness of the hard coating layer, so thecenter-line-average roughness of the antireflective film can be adjustedto the foregoing range by controlling the center-line-average surfaceroughness of the hard coating layer.

In addition to control of the surface roughness profile with theintention of keeping image sharpness, it is preferable to controltransmitted image definition. The definition of images transmitted bythe clear antireflective film is preferably 60% or above. Thetransmitted image definition is generally an index to the blur degree ofimages projected through film, and the greater value thereof means thatimages viewed through film are the higher in clarity and the better inquality. To be concrete, the transmitted image definition is preferably70% or above, far preferably 80% or above.

<Photoinitiator>

Examples of a radical photopolymerization initiator includeacetophenones, benzoins, benzophenones, phosphine oxides, ketals,anthraquinones, thioxanthones, azo compounds, peroxides(JP-A-2001-139663 and so on), 2,3-dialkyldione compounds, disulfidecompounds, fluoroamine compounds, aromatic sulfonium compounds, lophinedimers, onium salts, borate salts, active esters, active halogencompounds, inorganic complexes and coumarins.

These initiators may be used alone or as mixtures of two or morethereof.

Various examples thereof are also described in Saishin UV Koka Gijutsu,p. 159, K. K. Gijutu Joho Kyokai (1991), and Kiyoshi Kato, ShigaisenKoka System, pp. 65-148, Sogo Gijutsu Center (1989), and they are usefulin the invention, too.

Suitable examples of commercially available radical photopolymerizationinitiators include KAYACURE (DETX-S, BP-100, BDMK, CTX, BMS, 2-EAQ, ABQ,CPTX, EPD, ITX, QTX, BTC, MCA and so on, products of Nippon Kayaku Co.,Ltd.), IRGACURE (651, 184, 500, 819, 907, 369, 1173, 1870, 2959, 4265,4263 and so on, products of Ciba Specialty Chemicals Inc.), Esacure(KIP100F, KB1, EB3, BP, X33, KT046, KT37, KIP150 and TZT, products ofSartomer Company Inc.), and combinations of two or more of theseproducts.

It is appropriate that those photopolymerization initiators be used inan amount of 0.1 to 15 parts by mass (weight), preferably 1 to 10 partsby mass, per 100 parts by mass of multifunctional monomer(s).

<Surface Condition Improver>

For remedying surface condition troubles (including unevenness incoating, drying mark and point defect), it is favorable that a surfacecondition improver containing at least either a fluorine atom or asilicon atom is added to a coating solution used for making any oflayers on a substrate.

The surface condition improver used suitably is a compound capable ofchanging the surface tension of a coating solution by at least 1 mN/m.The expression “changing the surface tension of a coating solution by atleast 1 mN/m” means that the surface tension of a coating solution afteraddition of a surface condition improver, inclusive of the process ofconcentration during coating and drying, changes by at least 1 mN/m ascompared with the surface tension of a coating solution free of surfacecondition improver. It is preferable that the surface condition improverhas an effect of reducing the surface tension of a coating solution byat least 1 mN/m, preferably at least 2 mN/m, particularly preferably atleast 3 mN/m.

Suitable examples of a fluorine-containing surface condition improverinclude compounds containing fluoroaliphatic groups, and suitableexamples of such compounds include the compounds disclosed inJP-A-2005-115359, JP-A-2005-221963 and JP-A-2005-234476.

3. Antiglare Layer

An antiglare layer is provided for the purpose of contributing anantiglare property through surface scattering, preferably furthercontributing a hard coating property for enhancement of abrasionresistance, to the film.

As methods of contributing an antiglare property to the film, there areknown the method as disclosed in JP-A-6-16851 wherein an antiglare layeris formed by lamination of an embossed matte film having microscopicasperities on its surface, the method as disclosed in JP-A-2000-206317wherein surface roughness is formed through curing shrinkage differencecaused in an ionizing radiation curable resin by difference in amount ofexposure to ionizing radiation, the method as disclosed inJP-A-2000-338310 wherein transmissive fine particles and transmissiveresin are gelled and solidified through a decrease in a mass ratio of agood solvent to the transmissive resin by drying to result in formationof asperities on the coating surface, the method as disclosed inJP-A-2000-275404 wherein surface roughness is imparted by externallyapplied pressure, the method as disclosed in JP-A-2005-195819 whereinasperities are formed on the coating surface by utilizing phaseseparation in the process of evaporating a solvent from a solution oftwo or more polymers, and so on. And these known methods can be used inthe invention, too.

<Transmissive Particles>

A preferred aspect applicable to an antiglare layer for use in theinvention consists in that the antiglare layer contains a binder capableof imparting hard coating properties, transmissive particles forimparting an antiglare property and a solvent as essential ingredientsand surface roughness is formed with asperities of individualtransmissive particles themselves or aggregates in which those particlesgather. It is preferable that the antiglare layer having an antiglareproperty offers a compromise between the antiglare property and a hardcoating property.

Examples of transmissive particles used suitably in the antiglare layerinclude particles of inorganic compounds, such as silica particles andTiO₂ particles, and resin particles, such as acrylic resin particles,cross-linked acrylic resin particles, polystyrene particles,cross-linked styrene resin particles, melamine resin particles andbenzoguanamine resin particles. Of these particles, cross-linked styreneresin particles, cross-linked acrylic resin particles and silicaparticles are preferred over the others. The matting particles used maybe either spherical or indefinite in shape.

In addition, matting particles of two or more types different in sizemay be used together. It is possible to impart antiglare property by useof matting particles having greater sizes and another optical propertyby use of matting particles having smaller sizes. For instance, when anantiglare antireflective film is stuck on a high-definition displayhaving a pixel count of 133 ppi or above, a problem in point of displayimage quality, which is referred to as “glitter”, occurs in some cases.The glitter is brought about by loss of uniformity in brightness, whichresults from expansion or reduction of picture elements by microscopicasperities present on the antiglare antireflective film surface, so itcan be greatly improved by using matting particles which are smaller insize than matting particles used for imparting antiglare property anddifferent in refractive index from the binder.

The matting particles are incorporated into an antiglare layer so thattheir content in an antiglare hard-coating layer formed ranges from 10to 1,000 mg, preferably from 100 to 700 mg, per square meter.

The thickness of the antiglare layer is preferably from 1 to 20 μm, farpreferably from 2 to 10 μm. The thickness adjustment to such a range canserve a function as a hard coating, and also allows protection againstcurling and brittleness.

On the other hand, it is appropriate that the center-line-averageroughness (Ra) of the antiglare layer be adjusted to 0.10 μm or below,preferably 0.08 μm or below, far preferably 0.06 μm or below.

The strength of the antiglare layer is preferably H or higher, farpreferably 2H or higher, especially preferably 3H or higher, asdetermined by pencil hardness testing.

4. Low Refractive Index Layer

For reduction in reflectance of the present film, it is appropriate thata low refractive index layer be provided.

The refractive index of the low refractive index layer is preferablyfrom 1.20 to 1.46, far preferably from 1.25 to 1.46, particularlypreferably from 1.30 to 1.46.

The thickness of the low refractive index layer is preferably from 50 to200 nm, far preferably from 70 to 100 nm. The haze of the low refractiveindex layer is preferably 3% or below, far preferably 2% or below,especially preferably 1% or below. The concrete strength of the lowrefractive index layer, as evaluated by the pencil hardness test under aload of 500 g, is preferably at least H, far preferably at least 2H,especially preferably at least 3H.

In addition, for improvement in soil resistance of the antireflectivefilm, it is appropriate that the contact angle of the film surface withrespect to water be 90 degrees or above, preferably 95 degrees or above,particularly preferably 100 degrees or above.

Examples of an aspect of the curable composition suitable for formingthe low refractive index layer include (1) a composition including afluorine-containing polymer having cross-linkable or polymerizablefunctional groups, (2) a composition containing as a main component thehydrolytic condensation product of a fluorine-containing organosilanematerial, and (3) a composition containing a monomer having two or moreethylenically unsaturated groups and inorganic fine particles of hollowstructure.

4-(1) Fluorine-Containing Polymer Having Cross-Linkable or PolymerizableFunctional Groups

As an example of a fluorine-containing polymer having cross-linkable orpolymerizable functional groups, mention may be made of a copolymer of afluorine-containing monomer and a monomer having a cross-linkable orpolymerizable functional group. Examples of the fluorine-containingmonomer include fluoroolefin (such as fluoroethylene, vinylidenefluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropyleneand perfluoro-2,2-dimethyl-1,3-dioxol), partially or completelyfluorinated alkyl ester derivatives of (meth)acrylic acid (such asBiscoat 6FM, a product of Osaka Organic Chemical Industry Ltd., andM-2020, a product of Daikin Industries, Ltd.) and completely orpartially fluorinated vinyl ethers.

One aspect of the monomer used for imparting a cross-linking group is a(meth)acrylate monomer having in advance a cross-linkable functionalgroup in its molecule, such as glycidyl methacrylate. Another aspect ofthe monomer used for the foregoing purpose is a monomer having afunctional group, such as hydroxyl group, which is modified into across-linkable or polymerizable group through substitution aftercopolymerization with a fluorine-containing monomer. Examples of such amonomer include (meth)acrylate monomers each having a carboxyl group, ahydroxyl group, an amino group, a sulfonic acid group or the like (suchas (meth)acrylic acid, methylol(meth)acrylate,hydroxyalkyl(meth)acrylate and allyl acrylate). The latter aspect isdisclosed in JP-A-10-25388 and JP-A-10-147739.

In terms of solubility, dispersibility, coating characteristics, soilresistance and antistatic properties, the fluorine-containing copolymerscan contain copolymerizable components as appropriate. For the purposeof giving soil resistance and a slippery property in particular to thecopolymers, it is favorable to introduce silicone into either the mainchain, side chains or both.

As an example of a method of introducing a partial structure ofpolysiloxane into the main chain, mention may be made of the method asdisclosed in JP-A-6-93100 which uses a polymeric initiator, such as anazo group-containing polysiloxaneamide (commercially available productsof which include VPS-0501 and VPS-1001, trade names, products of WakoPure Chemical Industries, Ltd.). On the other hand, the introductioninto side chains can be performed, e.g., by using the method ofintroducing polysiloxane having a reactive group as its one end group(e.g., Silaplain series, produced by Chisso Corporation) by polymerreaction as described in J. Appl. Polym. Sci., 2000, 78, 1955, andJP-A-56-28219, or by synthesis according to the method of polymerizing apolysiloxane-containing silicone macromer. Both of these methods can befavorably used.

Those polymers may be used in combination with curing agents havingpolymerizable unsaturated groups, if needed, as disclosed inJP-A-2000-17028. In addition, as disclosed in JP-A-2002-145952, it ispreferable that those polymers are used in combination withfluorine-containing multifunctional compounds having polymerizableunsaturated groups. Examples of a polymerizable unsaturatedgroup-containing multifunctional compound include the monomers havingtwo or more ethylenically unsaturated groups per molecule. Moreover, thehydrolytic condensates of organosilanes as disclosed inJP-A-2004-170901, notably the hydrolytic condensates of (meth)acryloylgroup-containing organosilanes, can be used to advantage.

It is advantageous for these compounds to be used in combination withthe polymers, notably the polymers having polymerizable unsaturatedgroups in their main units, because such combinations can produce asignificant effect on enhancement of abrasion resistance.

When the curability of polymers themselves is not sufficient, therequired level of curability can be imparted to the polymers bycompounding the polymers and cross-likable compounds. When the polymershave, e.g., hydroxyl groups in their main units, it is preferable that avariety of amino compounds are used as curing agents. The amino compoundusable as a cross-linkable compound is a compound having at least twoamino groups chosen from, e.g., hydroxyalkylamino groups,alkoxyalkylamino groups, or both, with examples including melaminecompounds, urea compounds, benzoguanamine compounds and glycolurilcompounds. In the curing of these compounds, it is preferable thatorganic acids or salts thereof are used.

Examples of those fluorine-containing polymers include those disclosedin JP-A-2003-222702 and JP-A-2003-183322.

4-(2) Hydrolytic Condensate of Fluorine-Containing Organosilane Material

A composition containing hydrolytic condensate of a fluorine-containingorganosilane compound as the main component is also preferable, becauseit also has a low refractive index and can ensure highly hard coatingsurface. As the hydrolytic condensate, the condensate of a fluorinatedalkane having a hydrolyzable silanol group on one end or either endthereof and a tetraalkoxysilane compound is suitable. Examples of such acomposition include the compositions disclosed in JP-A-2002-265866 andJP-A-2002-317152.

4-(3) Composition Containing Monomer Having Two or More EthylenicallyUnsaturated Groups and Inorganic Fine Particles of Hollow Structure

Still another aspect of the low refractive index layer preferred in theinvention is a layer including a binder and particles of a lowrefractive index. The particles of a low refractive index, though may beeither inorganic or organic particles, are preferably particles havingholes on the inside. Examples of hollow particles include the silicaparticles disclosed in JP-A-2002-79616. The refractive index of thoseparticles is preferably from 1.15 to 1.40, far preferably from 1.20 to1.30. Examples of the binder include the monomers having two or moreethylenically unsaturated groups per molecule as described in theearlier section on the hard coating layer.

To the low refractive index layer for use in the invention, it isadvantageous to add any of the polymerization initiators as described inthe earlier section on the hard coating layer. When the composition forforming the low refractive index layer contains a radical polymerizablecompound, the polymerization initiator can be used in an amount of 1 to10 parts by mass, preferably 1 to 5 parts by mass, for the compound.

In the low refractive index layer for use in the invention, inorganicparticles can be incorporated. For imparting abrasion resistance, it isadvantageous to use fine particles having sizes ranging from 15% to150%, preferably from 30% to 100%, far preferably from 45% to 60%, ofthe thickness of the low refractive index layer.

For the purpose of imparting properties including soil resistance, waterresistance, chemical resistance and a slippery property, knownpolysiloxane- or fluorine-containing antifouling agents and slippingagents can be added to the low refractive index layer as appropriate.

5. High Refractive Index Layer and Middle Refractive Index Layer

The present film is provided with a high refractive index layer and amiddle refractive index layer, and these layers can enhanceantireflective property of the film in combination with the lowrefractive index layer by utilization of optical interference occurringbetween those layers.

Hereinafter, the high refractive index layer and the middle refractiveindex layer are sometimes collectively called a high refractive indexlayer. Incidentally, the adjectives “high”, “middle” and “low” in theterms “high refractive index layer”, “middle refractive index layer” and“low refractive index layer” describe a relative magnitude relationamong refractive indexes of layers. As for the refractive index relationwith the transparent substrate, it is preferable that the relations,transparent substrate>low refractive index layer and high refractiveindex layer>transparent substrate, are satisfied.

Sometimes in this specification a high refractive index layer, a middlerefractive index layer and a low refractive index layer are collectivelycalled “an antireflective layer”.

When the antireflective film is formed by providing a low refractiveindex layer on a high refractive index layer, the refractive index ofthe high refractive index layer is preferably from 1.50 to 2.40, farpreferably from 1.60 to 2.20, further preferably from 1.70 to 2.10,especially preferably from 1.80 to 2.00.

When the antireflective film is formed by providing on the conductivelayer a middle refractive index layer, a high refractive index layer anda low refractive index layer in order of increasing distance from thesubstrate, the refractive index of the high refractive index layer ispreferably from 1.60 to 2.10, far preferably from 1.70 to 2.00. And therefractive index of the middle refractive index layer is adjusted to avalue intermediate between the refractive index of the low refractiveindex layer and that of the high refractive index layer. The refractiveindex of the middle refractive index layer is preferably from 1.50 to1.70. Herein, the refractive index of the low refractive index layer ispreferably from 1.3 to 1.5.

Examples of inorganic particles used in the high refractive index layerand the middle refractive index layer include TiO₂, ZrO₂, Al₂O₃, In₂O₃,ZnO, SnO₂, Sb₂O₃, ITO and SiO₂. Of these fillers, TiO₂ and ZrO₂ arepreferred over the others from the viewpoint of heightening therefractive index. It is also preferable that the surface of such aninorganic filler is treated with a silane coupling agent or a titanatecoupling agent, and a surface treatment agent having a functional groupcapable of reacting with the binder is favorably applied to the fillersurface.

The content of such inorganic particles in the high refractive indexlayer is preferably from 10 to 90%, far preferably from 15 to 80%,particularly preferably from 15 to 75%, of the mass of the highrefractive index layer. Two or more kinds of inorganic particles may beused together in the high refractive index layer.

When the low refractive index layer is provided on the high refractiveindex layer, it is preferable that the refractive index of the highrefractive index layer is higher than that of the transparent substrate.

In the high refractive index layer, it is also possible to use a binderprepared by cross-linking or polymerization reaction of an ionizingradiation curable compound containing an aromatic ring, an ionizingradiation curable compound containing a halogenation element other thanfluorine (e.g., Br, I or Cl), or an ionizing radiation curable compoundcontaining an S, N or P atom.

The thickness of the high refractive index layer can be designedappropriately according to the intended use. When the high refractiveindex layer is used as an optical interference layer, the thicknessthereof is preferably from 30 to 200 nm, far preferably from 50 to 170nm, particularly preferably from 60 to 150 nm.

When the high refractive index layer does not contain particles forimparting an antiglare function, the lower the haze thereof the better.Specifically, the haze is preferably 5% or below, far preferably 3% orbelow, particularly preferably 1% or below.

<Coating Solvent>

In the layer applied so as to adjoin the base film among the foregoingconstituent layers, it is advantageous to incorporate at least one ormore solvents in which the base film is soluble and at least one or moresolvents in which the base film is insoluble. By having such an aspect,the adjoining layer not only can avoid excess impregnation of the basefilm with its ingredient(s) but also can ensure adhesion to the basefilm. In addition, it is preferable that at least one of the solvents inwhich the base film is soluble has a higher boiling temperature than atleast one of the solvents in which the base film is insoluble. And it ispreferable by far that the boiling temperature difference between thesolvent having the highest boiling point among the solvents in which thebase film is soluble and the solvent having the highest boiling pointamong the solvents in which the base film is insoluble is at least 30°C., especially at least 40° C.

The ratio of (A) the total amount of solvents in which the transparentbase film is soluble to (B) the total amount of solvents in which thetransparent base film is insoluble (the (A)/(B) ratio) is preferablyfrom 5/95 to 50/50 by mass, far preferably from 10/90 to 40/60 by mass,further preferably from 15/85 to 30/70 by mass.

6. Substrate

The substrate for use in the present film has no particular restriction,and it may be any of a transparent resin film, a transparent resin plateand a transparent resin sheet. Examples of a transparent resin filminclude cellulose acylate films (such as cellulose triacetate film(refractive index: 1.48), cellulose diacetate film, cellulose acetatebutyrate film or cellulose acetate propionate film), polyethyleneterephthalate film, polyether sulfone film, polyacrylic resin film,polyurethane resin film, polyester film, polycarbonate film, polysulfonefilm, polyether film, polymethylpentene film, polyether ketone film,(meth)acrylonitrile film, polyolefin film, film of a polymer havingalicyclic structures (e.g., film of norbornene resin (ARTON, trade name,a product of JSR Corporation)), and film of amorphous polyolefin(ZEONEX, trade name, a product of ZEON Corporation). Of these filmmaterials, triacetyl cellulose, polyethylene terephthalate and a polymerhaving alicyclic structures are preferred over the others. And triacetylcellulose in particular is used to advantage.

The thickness the substrate can have in the invention is generally ofthe order of 25 μm to 1,000 μm, preferably from 25 μm to 250 μm, farpreferably from 30 μm to 90 μm.

The substrate having any width can be used in the invention. From theviewpoints of handling, yield ratio and productivity, the substratehaving a width of 100 to 5,000 mm can generally be used. The width ofthe substrate is preferably from 800 to 3,000 mm, far preferably from1,000 to 2,000 nm. The substrate can be handled in the form of a longroll. The length of the roll is generally from 100 to 5,000 m,preferably from 500 to 3,000 m.

It is advantageous for the substrate to have a smooth surface, and theaverage roughness Ra of the substrate is preferably 1 μm or below, farpreferably from 0.0001 to 0.5 μm, further preferably from 0.001 to 0.1μm.

<Cellulose Acylate Film>

Of the various films, cellulose acylate films, which are generally usedas protective films of polarizing plates, are preferred over the othersbecause of their high transparency, slight optical birefringence andeasiness of manufacturing.

There are known various techniques for improving the mechanicalcharacteristics, transparency and planarity of cellulose acylate films.Of these known techniques, the techniques disclosed in Kokai Giho(Journal of Technical Disclosure), 2001-1745, are applicable to the filmfor use in the invention.

Of cellulose acylate films, cellulose triacetate film is preferred overthe others in the invention, and cellulose acetate film as a celluloseacylate film having an acetylation degree of 59.0 to 61.5% is used toadvantage. The term “acetylation degree” as used herein refers to theamount of acetic acid bonded per unit mass of cellulose. And theacetylation degree follows the measurement and calculation ofacetylation degree in ASTM: D-817-91 (the testing method for celluloseacetate and the like).

The viscosity-average polymerization degree (DP) of cellulose acylate ispreferably 250 or above, far preferably 290 or above.

It is preferable that the cellulose acylate used in the invention has aMw/Mn value close to 1.0 (where Mw is mass-average molecular weight, andMn is number-average molecular weight), which can be determined by gelpermeation chromatography. In other words, the cellulose acylatepreferably has a narrow molecular-weight distribution. Specifically, thesuitable Mw/Mn value is from 1.0 to 1.7, preferably from 1.3 to 1.65,especially preferably from 1.4 to 1.6.

In general the total substitution degree is not shared equally ⅓ by ⅓among the hydroxyl groups in the 2-, 3- and 6-positions of celluloseacylate, but the substitution degree of 6-position hydroxyl groups tendsto be smaller than those of 2- and 3-position hydroxyl groups. In thecellulose acylate used in the invention, however, the substitutiondegree of 6-position hydroxyl groups is preferably greater than those of2- and 3-hydroxyl groups.

It is appropriate that the 6-position hydroxyl groups be substituted byacyl groups in a proportion of at least 32%, preferably at least 33%,particularly preferably at least 34%, of the total substitution degree.In addition, it is preferable that the substitution degree of the6-position acyl groups in the cellulose acylate is 0.88 or above. Inaddition to acetyl group, the 6-position hydroxyl groups may besubstituted by acyl groups containing 3 or more carbon atoms, such aspropionyl, butyroyl, valeloyl, benzoyl and acryloyl groups. Thesubstitution degree in each position can be determined by NMRmeasurements.

The cellulose acetates prepared by the methods disclosed inJP-A-11-5851, Examples, paragraphs [0043] to [0044] Synthesis Example 1,paragraphs [0048] to [0049] Synthesis Example 2, and paragraphs [0051]to [0052] Synthesis Example 3, can be used as cellulose acylate for usein the invention.

<Polyethylene Terephthalate Film>

As a substrate film used in the invention, polyethylene terephthalatefilm is also preferred because it has excellent transparency, mechanicalstrength, planarity, chemical resistance and moisture resistance, what'smore it is cheap.

For enhancement of the adhesion strength between a transparent plasticfilm and the hard coating layer, the use of transparent plastic filmhaving undergone easily-adhering treatment is preferable by far.

As examples of commercially available optical PET film with aneasily-adhering layer, mention may be made of COSMOSHINE A4100 andA4300, products of Toyobo Co., Ltd.

7. Coating Method

Each constituent layer of the present film can be formed using variousmethods including but not limited to the following methods.

Specifically, the coating methods usable herein include known methods,such as a dip coating method, an air knife coating method, a curtaincoating method, a roller coating method, a wire-bar coating method, agravure coating method, an extrusion coating method (a die coatingmethod) (see U.S. Pat. No. 2,681,294), and a microgravure coatingmethod. Of these methods, a microgravure coating method and a diecoating method are preferred over the others.

The microgravure coating method usable in the invention is a coatingmethod characterized in that a gravure roll having a diameter of about10 mm to about 100 mm, preferably about 20 mm to about 50 mm, and agravure pattern engraved all around the periphery is placed underneath asubstrate and brought to a state of rotation in the direction oppositeto a transport direction of the substrate, and application of a coatingsolution is performed by transferring a coating solution fed on thegravure roll surface in an amount kept constant by scraping an excesscoating solution off the gravure roll surface with a doctor blade to theunder surface of the substrate in a position where the upper surface ofthe substrate is in a free state. A transparent substrate in a roll formis continuously wound off, and thereon at least either the hard coatinglayer or at least one of low refractive index layers containingfluorine-containing olefin polymers can be coated by the microgravurecoating method.

As to the coating conditions in the microgravure coating method, theline number of a gravure pattern engraved on the gravure roll ispreferably from 50 to 800 per inch, far preferably from 100 to 300 perinch, the depth of the gravure pattern is preferably from 1 to 600 μm,far preferably from 5 to 200 μm, the revs of the gravure roll ispreferably from 3 to 800 rpm, far preferably from 5 to 200 rpm, and thetransport speed of a substrate is preferably from 0.5 to 100 m/min, farpreferably from 1 to 50 m/min.

For supplying of the present film with high productivity, the adoptionof an extrusion method (a die coating method) is favorable. In theregion of a small wet coverage (20 cc/m² or below) in particular, suchas in the case of a hard coating layer or an antireflective layer, theadoption of the manufacturing method disclosed in JP-A-2006-122889allows enhancement of coating film uniformity.

8. Polarizing Plate

The present film is used as protective film arranged on one side oreither side of a polarizer and, together with the polarizer, can form apolarizing plate.

Although the present film may be used as one of the protective films andcommonly used cellulose acetate film may be used as the other protectivefilm, it is advantageous to use as the other protective film a celluloseacetate film made by the solution film-formation method and stretched ata stretch ratio of 10 to 100% in the width direction of the film in aroll form.

As polarizers, there are known an iodine polarizer, a dye polarizerusing a dichroic dye and a polyene polarizer. The iodine polarizer andthe dye polarizer are generally formed using polyvinyl alcohol film.

The slow axes of the transparent substrate of the antireflective filmand the cellulose acetate film and the transmission axis of thepolarizer are positioned so as to become parallel in a substantialsense.

Moisture permeability of protective films is important for productivityof a polarizing plate. The polarizer and the protective films are bondedtogether with an aqueous adhesive, and this adhesive solvent is dried bydiffusion through the protective films. The higher the moisturepermeability of the protective films, the faster the drying becomes andthe more the productivity is improved. However, when the moisturepermeability becomes too high, permeation of moisture into thepolarizers occurs depending on the use environment of a liquid crystaldisplay (under high humidity) to result in lowering of polarizationpower.

The determination of what moisture permeability the protective filmshave is based on the thicknesses, free volumes, and hydrophilic orhydrophobic degrees of the transparent substrate and the polymer film(and the polymerizable liquid crystal compound).

When the present film is used as a protective film of a polarizingplate, the moisture permeability thereof is preferably from 100 to 1,000g/m²·24 hrs, far preferably from 300 to 700 g/m²·24 hrs.

When the film is manufactured, the thickness of a transparent substratecan be controlled by a lip flow rate and line speed, or by stretching orcompression. As the moisture permeability varies with main materialsused, it can be adjusted to the desired range by thickness control.

In the case of manufacturing the film, the free volume of thetransparent substrate can be controlled by drying temperature and timeadopted.

In this case also, the moisture permeability can be adjusted to thedesired range by free volume control since it varies with main materialsused.

The hydrophilic or hydrophobic degree of the transparent substrate canbe controlled by additives. The moisture permeability is heightened byaddition of hydrophilic additives to the free volume, while addition ofhydrophobic additives lowers the moisture permeability.

By independent control of the moisture permeability, it becomes possibleto manufacture a polarizing plate having an optically compensatory powerat low cost and with high productivity.

The polarizer may be any of known polarizers, or may be a polarizer cutfrom a long length of polarizer whose absorption axis is neitherparallel nor perpendicular to the direction of the length. The polarizerwhose absorption axis is neither parallel nor perpendicular to thedirection of the length is formed in the following manner.

Specifically, such a polarizer can be formed by stretching acontinuously supplied polymer film under a tension while holding bothedges thereof with holding tools. Herein, the polymer film is stretchedto 1.1 to 20.0 times its original length in the direction of the width.In addition, the longitudinally traveling speed difference between thefilm-edge holding tools is controlled to 3% or below, and the travelingdirection of the film is bend as the film edges are held with theholding tools so that the film traveling direction at the exit from thefilm edge holding process tilts 20 to 70 degrees toward the substantialstretch direction of the film. The 45° tilt of the film travelingdirection is especially advantageous from the viewpoint of productivity.

Detailed description of the polymer film stretching method can be foundin JP-A-2002-86554, paragraphs [0020] to [0030].

Of two protective films for a polarizer, it is also preferable that thefilm other than the antireflective film is an optically compensatoryfilm having optically compensatory layers including an opticallyanisotropic layer. The optically compensatory film (retardation film)can improve viewing angle characteristics of a liquid crystal displayscreen.

As to the optically compensatory film, though any of known ones can beused, the optically compensatory film disclosed in JP-A-2001-100042 ispreferable in point of viewing angle increase.

9. Usage Pattern of The Invention

The present film can be used in image display devices including a liquidcrystal display device (LCD), a plasma display panel (PDP), anelectroluminescent display (ELD) and a cathode-ray tube display device(CRT). Optical filters according to the invention can be used on knowndisplays, such as plasma display panels (PDP) and cathode-ray tubedisplay devices (CRT).

9-(1) Liquid Crystal Display Device

The present film and polarizing plate can be used with advantage inimage display devices including a liquid crystal display device, and itis preferable that they are used as the outermost layers of displays.The crystal display device has a liquid crystal cell and two polarizingplates disposed on both side of the liquid crystal cell. The liquidcrystal cell holds liquid crystal between two electrode plates. Inaddition, an optically anisotropic layer is arranged between the liquidcrystal cell and one of the polarizing plates or, in some cases, twooptically anisotropic layers are arranged between the liquid crystalcell and the two polarizing plates each.

The crystal cell is preferably a TN-mode, VA-mode, OCB-mode, IPS-mode orECB-mode crystal cell.

<TN Mode>

In a TN-mode liquid crystal cell, rod-shaped liquid crystallinemolecules are aligned in a substantially horizontal direction, and thatin a state of being twisted by 60° to 120°, when no voltage is appliedthereto.

TN-mode crystal cells are prevailingly utilized in color TFT liquidcrystal display devices, and described in an abundant technicalliterature.

<VA Mode>

In a VA-mode liquid crystal cell, rod-shaped liquid crystallinemolecules align in a substantially vertical direction when no voltage isapplied thereto.

VA-mode liquid crystal cells include not only (1) a strict sense ofVA-mode liquid crystal cell in which, while rod-shaped liquidcrystalline molecules align in a substantially vertical direction whenno voltage is applied thereto, they are forced to align in asubstantially horizontal direction by application of a voltage thereto(as disclosed in JP-A-2-176625), but also (2) a multidomain VA-mode(MVA-mode) liquid crystal cell which ensures a viewing angle increase(as described in SID 97 Digest of Tech. Papers (preprints) 28, p.845(1997)), (3) an n-ASM-mode liquid crystal cell in which rod-shapedliquid crystalline molecules align in a substantially vertical directionwhen no voltage is applied thereto, but they are brought into a twistedmultidomain alignment by application of a voltage thereto (as describedin preprints of Nippon Ekisho Toronkai (Symposium on Liquid Crystal),pp. 58-59 (1998)), and (4) a SURVAIVAL-mode liquid crystal cell(announced at LCD International 98).

<OCB Mode>

The liquid crystal cell of OCB mode is a liquid crystal cell of bendalignment mode in which rod-shaped liquid crystalline molecules in theupper part and those in the lower part are forced to align(symmetrically) in substantially opposite directions, and examplesthereof are disclosed in U.S. Pat. Nos. 4,583,825 and 5,410,422. Sincethe rod-shaped liquid crystal molecules are symmetrically aligned in theupper part and the lower part of a liquid crystal cell, the bendalignment mode liquid crystal cell has an optically self-compensatoryfunction. Therefore, this liquid crystal mode is referred to as an OCB(Optically Compensatory Bend) liquid crystal mode. The liquid crystaldisplay devices of the bend alignment mode have an advantage of highresponse speed.

<IPS Mode>

The liquid crystal cell of IPS mode adopts a mode of switching byapplication of a lateral electric field to nematic liquid crystal, anddetails thereof are described in Proc. IDRC (Asia Display '95), pp.577-580 and pp. 707-710.

<ECB Mode>

In an ECB-mode liquid crystal cell, rod-shaped liquid crystallinemolecules are aligned in a substantially horizontal direction. The ECBmode is one of liquid crystal display modes having the most simplestructures, and described, e.g., in JP-A-5-203946.

9-(2) Displays Other Than Liquid Crystal Display Device

<PDP>

A plasma display panel (PDP) is generally made up of a gas, glasssubstrates, electrodes, an electrode lead material, a thick-film printmaterial and fluorescent substances. The glass substrates are a frontglass substrate and a rear glass substrate. Each glass substrate isprovided with an electrode and an insulation layer. The rear glasssubstrate is further provided with phosphor layers. These two glasssubstrates are assembled, and a gas is sealed into a space between them.

Plasma display panels are already commercially available. Descriptionsthereof can be found in JP-A-5-205643 and JP-A-9-306366.

In some cases, a front plate is placed in front of a plasma displaypanel. It is appropriate that the front plate be strong enough toprotect the plasma display panel. The front plate can be used in a statethat there is a clearance between the front plate and the plasma displaypanel, or in a state that the front plate is bonded directly to theplasma display panel proper.

In an image display such as a plasma display panel, an optical filtercan be stuck directly on the display surface. When a front plate isprovided in front of the display, the optical filter may be stuck oneither the front side (outside) or rear side (display side) of the frontplate.

<Touch Panel>

The present film can be applied to touch panels as disclosed inJP-A-5-127822 and JP-A-2002-48913.

Moreover, the present film can be used as a protective film of anorganic electroluminescent device or so on.

When the present film is used in an organic electroluminescent device,the descriptions in JP-A-11-335661, JP-A-11-335368, JP-A-2001-192651,JP-A-2001-192652, JP-A-2001-192653, JP-A-2001-335776, JP-A-2001-247859,JP-A-2001-181616, JP-A-2001-181617, JP-A-2002-181816, JP-A-2002-181617and JP-A-2002-056976 are applicable. In addition, it is preferable thatthose descriptions are used in combination with the descriptions inJP-A-2001-148291, JP-A-2001-221916 and JP-A-2001-231443.

EXAMPLES

Now, the invention is described in more detail on the basis of thefollowing examples, but these examples should not be construed aslimiting the scope of the invention.

Preparation of Coating Solution for Hard Coating Layer

Composition of Coating Solution H-1 for Hard Coating Layer PET-30 51.0 gDPHA 10.0 g Irgagure 184  2.0 g SX-350 (30%)  2.0 g Cross-linkedacrylic-styrene 13.0 g resin particles (30%) SP-13 0.06 g Toluene 38.5 g

Composition of Coating Solution H-2 for Hard Coating Layer PET-30 28.0 gDPHA 12.0 g Cohesive silica  5.0 g (secondarily aggregated grain size:1.5 μm) IRGACURE 184  1.0 g IRGACURE 907  0.2 g SP-13 0.08 g Methylisobutyl ketone 40.0 g Cyclohexanone 15.0 g

Composition of Coating Solution H-3 for Hard Coating Layer DESOLITEZ7404 100.0 g  DPHA 31.0 g KBM-5103 10.0 g KE-P150  8.9 g MXS-300  3.4 gMEK (Methyl ethyl ketone) 29.0 g MIBK (Methyl isobutyl ketone) 13.0 g

Composition of Coating Solution H-4 for Hard Coating Layer PET-30 28.0 gDPHA 12.0 g IRGACURE 184  1.0 g IRGACURE 907  0.2 g SP-13 0.08 g Methylisobutyl ketone 40.0 g Cyclohexanone  5.0 g

The coating solutions described above were each passed through apolypropylene filter having a pore size of 30 μm, thereby preparingCoating Solutions H-1 to H-4 for hard coating layers. The ingredientsused in H-1 to H-3 are specified below.

-   -   DPHA: Mixture of dipentaerythritol pentaacrylate and        dipehntaerythritol hexaacrylate (produced by Nippon Kayaku Co.,        Ltd.)    -   PET-30: Mixture of pentaerythritol triacrylate and        pentaerythritol tetraacrylate (produced by Nippon Kayaku Co.,        Ltd.)    -   IRGACURE 184: Polymerization initiator (produced by Ciba        Specialty Chemicals Inc.)    -   IRGACURE 907: Polymerization initiator (produced by Ciba        Specialty Chemicals Inc.)    -   SX-350: Cross-linked polystyrene particles having an average        size of 3.5 μm (refractive index: 1.60, a 30% toluene        dispersion, produced by Soken Chemical & Engineering Co., Ltd.        and used after undergoing dispersion operation for 20 minutes at        10,000 rpm by means of a polytron dispersing machine)    -   Cross-linked acrylic-styrene resin particles: Particles having        an average particle size of 3.5 μm (refractive index: 1.55, 30%        toluene dispersion, produced by Soken Chemical & Engineering        Co., Ltd. and used after undergoing dispersion operation for 20        minutes at 10,000 rpm by means of a polytron dispersing machine)    -   SP-13: Fluorine-containing surface modifier of the following

-   -   Cohesive silica: Silica having a secondarily aggregated grain        size of 1.5 μm (primary grain size: dozens nm), produced by        TOSOH SILICA CORPORATION    -   DESOLITE Z7404: Photopolymerizable hard-coating liquid        composition containing zirconia fine particles (produced by JSR        Corporation)    -   KBM-5103: γ-Acryloyloxypropyltrimethoxysilane (produced by        Shin-Etsu Chemical Co., Ltd.)    -   KE-P 150: 1.5-μm Silica particles (produced by Nippon Shokubai        Co., Ltd.)    -   MXS-300: 3-μm Cross-linked PMMA particles (produced by Soken        Chemical & Engineering Co., Ltd.)

Preparation of Coating Solution for Conductive Layer Preparation ofTransparent Conductive Material Preparation of Complex of π-ConjugatedConductive Polymer and Polymer Dopant <C-1> Preparation of Complex ofPoly(ethylenedioxythiophene) and Polyallylsulfonic Acid (TransparentConductive Material C-1)

Ethylenedioxythiophene in an amount of 14.2 g (0.1 mol) was mixed with asolution prepared by dissolving 0.15 mol of polyallylsulfonic acid in2,000 ml of ion-exchanged water.

This mixture was kept at 20° C. with stirring, and thereto an oxidationcatalyst solution prepared by dissolving 29.64 g (0.13 mol) of ammoniumpersulfate and 8.0 g (0.02 mol) of ferric sulfate in 200 ml ofion-exchanged water was added slowly. Herein, reaction was performed for5 hours with stirring.

The reaction solution thus obtained was admixed with 2,000 ml ofion-exchanged water, and about 2,000 ml of solution was removed byultrafiltration. This operation was repeated three times.

The water in the solution thus obtained was removed under reducedpressure, and a solid matter of polyallylsulfonic acid-dopedpoly(ethylenedioxythiophene) was obtained. This solid matter was mixedwith a solution described hereinafter, thereby preparing a transparentconductive material C-1.

<C-2> Preparation of Complex of Poly(ethylenedioxythiophene) andPolyallylsulfonic Acid-Polyallylamine Copolymer (Transparent ConductiveMaterial C-2)

Ethylenedioxythiophene in an amount of 14.2 g (0.1 mol) was mixed with asolution prepared by dissolving 0.15 mol of polyallylsulfonicacid-polyallylamine copolymer (copolymerization ratio: 80/10 by mole) in2,000 ml of ion-exchanged water.

This mixture was kept at 20° C. with stirring, and thereto an oxidationcatalyst solution prepared by dissolving 29.64 g (0.13 mol) of ammoniumpersulfate and 8.0 g (0.02 mol) of ferric sulfate in 200 ml ofion-exchanged water was added slowly. Herein, reaction was performed for5 hours with stirring.

The reaction solution thus obtained was admixed with 2,000 ml ofion-exchanged water, and about 2,000 ml of solution was removed byultrafiltration. This operation was repeated three times.

The water in the solution thus obtained was removed under reducedpressure, and a solid matter of polyallylsulfonic acid-polyallylaminecopolymer-doped poly(ethylenedioxythiophene) was obtained. This solidmatter was mixed with a solution described hereinafter, therebypreparing a transparent conductive material C-2.

<C-3> Preparation of Complex of Poly(ethylenedioxythiophene) andPolyallylsulfonic Acid-Poly(2-vinylethanol) Copolymer (TransparentConductive Material C-3)

Ethylenedioxythiophene in an amount of 14.2 g (0.1 mol) was mixed with asolution prepared by dissolving 0.15 mol of polyallylsulfonicacid-poly(2-vinylethanol) copolymer (copolymerization ratio: 80/10 bymole) in 2,000 ml of ion-exchanged water.

This mixture was kept at 20° C. with stirring, and thereto an oxidationcatalyst solution prepared by dissolving 29.64 g (0.13 mol) of ammoniumpersulfate and 8.0 g (0.02 mol) of ferric sulfate in 200 ml ofion-exchanged water was added slowly. Herein, reaction was performed for5 hours with stirring.

The reaction solution thus obtained was admixed with 2,000 ml ofion-exchanged water, and about 2,000 ml of solution was removed byultrafiltration. This operation was repeated three times.

The water in the solution thus obtained was removed under reducedpressure, and a solid matter of polyallylsulfonicacid-poly(2-vinylethanol) copolymer-doped poly(ethylenedioxythiophene)was obtained. This solid matter was mixed with a solution describedhereinafter, thereby preparing a transparent conductive material C-3.

Preparation of Sol a-1 of Oligomeric Cross-linking Site-forming Compound

In a 1,000-ml reaction vessel equipped with a thermometer, a nitrogenfeed tube and a dropping funnel, 118.2 g (0.50 mol) of Y-1, 117.2 g(0.50 mol) of Z-1, 320 g (10 mol) of ethanol and 0.06 g (0.001 mol) ofKF were put, and thereto 15.1 g (0.86 mol) of water was slowly addeddropwise at room temperature with stirring. After conclusion of dropwiseaddition, stirring was continued for 3 hours at room temperature, andthen heating and stirring was continued for 2 hours under reflux ofmethanol. Thereafter, low volatile components were distilled away underreduced pressure. The residue obtained was further filtered to yield 120g of Sol a-1. By GPC measurement, the mass-average molecular weight ofthe substance thus obtained was found to be 2,000, so the obtainedsubstance was identified as an oligomer.

Preparation of Sol a-2 of Oligomeric Cross-linking Site-forming Compound

In a 1,000-ml reaction vessel equipped with a thermometer, a nitrogenfeed tube and a dropping funnel, 234.4 g (1.00 mol) of Z-1, 320 g (10mol) of ethanol and 0.06 g (0.001 mol) of KF were put, and thereto 15.1g (0.86 mol) of water was slowly added dropwise at room temperature withstirring. After conclusion of dropwise addition, stirring was continuedfor 3 hours at room temperature, and then heating and stirring wascontinued for 2 hours under reflux of methanol. Thereafter, low volatilecomponents were distilled away under reduced pressure. The residueobtained was further filtered to yield 120 g of Sol a-2. By GPCmeasurement, the mass-average molecular weight of the substance thusobtained was found to be 1,800, so the obtained substance was identifiedas an oligomer.

Composition of Coating Solution for Conductive Layer Transparentconductive material 32.5 g Cross-linking site-forming compound 23.5 gPET-30 adjusted so that the sum of its amount and the amount ofcross-linking site-forming compound is 26.5 g IRGACURE 184  1.0 g SP-130.05 g MEK (methyl ethyl ketone) 40.0 g Isopropanol 20.0 g

Preparation of Coating Solution for Low Refractive Index LayerPreparation of Sol b

In a reaction vessel equipped with a stirrer and a reflux condenser, 120parts of methyl ethyl ketone, 100 parts ofacryloyloxypropyltrimethoxysilane (KBM-5103, produced by Shin-EtsuChemical Co., Ltd.) and 3 parts of diisopropoxyaluminumethylacetoacetate were put, mixed with one another, then further admixedwith 30 parts of ion-exchanged water, and underwent reaction at 60° C.for 4 hours. Thereafter, the reaction mixture was cooled to roomtemperature, thereby preparing Sol b. The mass-average molecular weightof Sol b was found to be 1,600, and besides, it was ascertained that allof the polymeric components higher than oligomers had their molecularweight in the range of 1,000 to 20,000. Moreover, gas chromatographyanalysis showed that acryloyloxypropyltrimethoxysilane as a raw materialfor the reaction didn't remain at all.

Preparation of Dispersion A

To 500 g of a hollow fine-particle silica sol (an isopropyl-alcoholsilica sol, having an average particle diameter of 60 nm and a shellthickness of 10 nm, a silica concentration of 20 mass %, containingsilica particles with a refractive index of 1.31, and prepared accordingto Preparation Example 4 in JP-A-2002-79616, except that the particlesizes were changed), 30 g of acryloyloxypropyltrimethoxysilane (producedby Shin-Etsu Chemical Co., Ltd.) and 1.5 g of diisopropoxyaluminumethylacetate were added, and they were mixed together. Thereto, 9 g ofion-exchanged water was added. This admixture underwent reaction at 60°C. for 8 hours, then cooled to room temperature, and further admixedwith 1.8 g of acetyl acetone. This dispersion in an amount of 500 g wassubjected to solvent displacement by performing reduced-pressuredistillation while adding cyclohexanone thereto so as to keep almost thesame silica content. The dispersion prepared was free of extraneousmatter, and its viscosity at 25° C. was 5 mPa·s as measured afteradjustment of its solid concentration to 20 mass % by use ofcyclohexanone. The proportion of residual isopropyl alcohol inDispersion A thus prepared was found to be 1.5% by gas chromatographicanalysis.

Preparation of Coating Solution L-1 for Low Refractive Index Layer

A coating Solution L-1 for a low refractive index layer was prepared bymixing 13 g of a thermally cross-linkable fluorinated polymer containingpolysiloxane and hydroxyl groups and having a refractive index of 1.44(JTA113, solid concentration: 6%, produced by JSR Corporation), 1.3 g ofa colloidal silica dispersion MEK-ST-L (trade name, average particlesize: 45 nm, solid concentration: 30%, produced by Nissan ChemicalIndustries, Ltd.), 0.65 g of the Sol b, 4.4 g of methyl ethyl ketone and1.2 g of cyclohexanone, stirring these ingredients, and then filteringthe resultant mixture through a polypropylene filter having a pore sizeof 1 μm. The refractive index of a layer formed with this coatingsolution was found to be 1.45.

Preparation of Coating Solution L-2 for Low Refractive Index Layer

In 500 g of methyl ethyl ketone, 37.6 g of a thermally cross-linkablefluorine-containing polymer (the fluorine- and silicone-containingthermosetting polymer disclosed in Example 1 of JP-A-11-189621), 9.40 gof a curing agent (Cymel 303, trade name, produced by Nihon CytecIndustries Inc.) and 0.92 g of a curing catalyst (Catalyst 4050, tradename, produced by Nihon Cytec Industries Inc.) were dissolved. Theretowere further added 195 parts by mass of Dispersion A (39.0 parts by massof silica plus solid content in the surface treatment agent), 30.0 partsby mass (9.0 parts by mass as the solid content) of a colloidal silicadispersion (silica: a product identical to MEK-ST except for theparticle size, average particle size: 45 nm, solid concentration: 30%,produced by Nissan Chemical Industries, Ltd.), 17.0 parts by mass (5.0parts by mass as the solid content) of Sol b and 0.3 parts by mass ofPM980M (a photopolymerization initiator, produced by Wako Pure ChemicalIndustries, Ltd.). The resulting mixture was diluted with cyclohexaneand methyl ethyl ketone so that the solids concentration in the wholecoating solution became 6 mass % and the ratio of cyclohexane to methylethyl ketone stood at 8:92, thereby preparing a coating Solution L-2 fora low refractive index layer. The refractive index of the layer formedwith this coating solution was found to be 1.38.

Preparation of Coating Solution L-3 for Low Refractive Index Layer

In 500 g of methyl isobutyl ketone, 45.0 g of an ethylenicallyunsaturated group-containing fluorinated polymer as solid component (thefluorinated polymer (A-1) disclosed in Synthesis Example 3 ofJP-A-2005-89536) was dissolved, and thereto were further added 195 partsby mass of Dispersion A (39.0 parts by mass of silica plus solid contentin the surface treatment agent), 30.0 parts by mass (9.0 parts by massas the solid content) of a colloidal silica dispersion (silica: aproduct identical to MEK-ST except for the particle size, averageparticle size: 45 nm, solid concentration: 30%, produced by NissanChemical Industries, Ltd.), 17.0 parts by mass (5.0 parts by mass as thesolid content) of Sol b and 2.0 parts by mass of PM980M (aphotopolymerization initiator, produced by Wako Pure ChemicalIndustries, Ltd.). The resulting mixture was diluted with methyl ethylketone so that the solids concentration in the whole coating solutionbecame 6 mass %, thereby preparing a coating Solution L-3 for a lowrefractive index layer. The refractive index of the layer formed withthis coating solution was found to be 1.38.

Preparation of Coating Solution L-4 for Low Refractive Index Layer

A fluorine compound having fluoroalkyl groups and polysiloxanestructures, OPSTER JTA105 (solid content: 5 weight %, a product of JSRCorporation) in an amount of 100 parts by weight was mixed with 1 partsby weight of OPSTER JTA105A (solid content: 5 weight %, a product of JSRCorporation), 151.5 parts by weight of butyl acetate and 164.0 parts byweight of a siloxane oligomer, COLCOAT N103X (a product of COLCOAT Co.,Ltd., number-average molecular weight: 950 as calculated in terms ofethylene glycol, solid content: 2 weight %). To this mixture was furtheradded 42.5 g of a hollow fine-particle silica sol (an isopropyl-alcoholsilica sol, having an average particle diameter of 60 nm and a shellthickness of 10 nm, a silica concentration of 20 mass %, containingsilica particles with a refractive index of 1.31, and prepared accordingto Preparation Example 4 in JP-A-2002-79616, except that the particlesizes were changed), thereby preparing a coating Solution L-4 for a lowrefractive index layer. The refractive index of the layer formed withthis coating solution was found to be 1.36.

<Method of Coating Antireflective Film>

Triacetyl cellulose film (TAC-TD80U, produced by FUJIFILM Corporation)in a roll form was wound off, and thereto the coating solution for ahard coating layer was applied by direct extrusion with a coater havinga slot die. The application was carried out on the condition that thetransport speed was 30 m/min, and the coating applied was dried at 30°C. for 15 seconds, and further dried at 90° C. for 20 seconds. The thusformed coating layer was cured by UV irradiation using a 160 W/cmair-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) in anexposure amount of 90 mJ/cm² under purge by nitrogen. Thus, a 5.0-μmthick hard coating layer having antiglare properties was formed, andwound into a roll.

In addition, the coating solution for a conductive layer was applied tothe hard coating layer surface by means of a coater having a slot die.The application was carried out on the condition that the transportspeed was 30 m/min, and the coating applied was dried at 30° C. for 15seconds, and further dried at 90° C. for 20 seconds. The thus formedcoating layer was cured by UV irradiation using the 160 W/cm air-cooledmetal halide lamp (made by Eye Graphics Co., Ltd.) in an exposure amountof 90 mJ/cm² under purge by nitrogen. The thickness of the conductivelayer thus applied and cured was found to be 0.8 μm.

On the conductive layer of the thus obtained coating film, the coatingsolution for a low refractive index layer was coated by direct extrusiononto the surface on the side of a backup roll where the hard coatinglayer was coated, thereby forming a 100-nm-thick low refractive indexlayer. The film thus coated was wound into a roll to make anantireflective film. The drying and curing conditions adopted are asfollows.

-   -   Drying: 90° C., 60 seconds.    -   Curing: Heating at 110° C. for 10 minutes and subsequent curing        by UV irradiation using a 240 W/cm air-cooled metal halide lamp        (made by Eye Graphics Co., Ltd.) in an exposure amount of 400        mJ/cm² under an atmosphere whose oxygen concentration was        reduced to 0.1% by purge with nitrogen.        <Evaluation Method>        (Integrated Reflectance)

The back of the film is roughened with sand paper, and treated withblack ink to avoid back reflection. In this state, the film surface isexamined for integrated spectral reflectances in the wavelength regionof 380 to 780 nm at an incident angle of 5° by means of aspectrophotometer (made by JASCO Corporation). As a measurement result,the arithmetic mean of integrated reflectances in the wavelength regionof 450 to 650 nm is adopted. The integrated reflectances of 2.7% orbelow can ensure sufficient antireflective properties, and the smallervalue means the better antireflective properties.

(Steel Wool Abrasion Resistance)

Steel wool is made to move to and fro on a film surface 10 times whileimposing thereon a load of 200 g/cm², and the state of abrasion on thefilm surface is observed. Abrasion resistance is rated on a 1-to-5 scale(5 being best), and criteria adopted are as follows.

5: No abrasion

4: Only slight, hardly-perceivable abrasion

3: Clearly-visible abrasion

2: Clearly-visible heavy abrasion

1: Exfoliation of film

(Adhesion)

In the surface on the antireflective film's low refractive index layerside, incisions spaced every 1 mm are made with a cutter knife in a gridpattern of 11 lines long by 11 lines wide, thereby carving 100 squaresin total. Adhesion test including a step of sticking apressure-sensitive adhesive polyester tape made by Nitto DenkoCorporation (NO. 31B) to the film surface with those incisions byapplication of pressure is repeated three times at the same place. Thenumber of squares peeled off is examined by visual observation. Criteriaadopted for evaluating the adhesion are as follows.

-   -   A: None of 100 squares is observed peeling off.    -   B: Two or fewer of 100 squares are observed peeling off.    -   C: Three to ten of 100 squares are observed peeling off.    -   D: Ten or more of 100 squares are observed peeling off.        (Evaluation of Surface Resistance)

The surface on the antireflective film's low refractive index layer side(outermost layer) is examined for surface resistance by using anultrahigh-insulation-resistance/micro ammeter, TR8601 (made by ADVANTESTCorporation) under a 25° C.-60% RH condition.

The surface resistance value is represented by logSR (logarithm), withthe value expressed in the unit Ω/square being taken as SR. Sufficientantistatic properties can be ensured so long as the value of logSR is11.0 or below.

Example 1

Antireflective film Samples 101 to 107 having the compositions shown inTable 1 were made, and evaluated by the methods described above.

TABLE 1 Conductive Layer Cross-linking Low Steel Hard TransparentSite-Forming Refractive Integrated Wool Coating Conductive CompoundIndex Reflectance Abrasion Sample Layer Layer (Amount added) Layer (%)logSR Adhesion Resistance Note 101 H-1 C-1 X-1 (6.4 g) L-1 2.6 10.3 B 3Invention 102 ″ ″ X-2 (6.4 g) ″ 2.6 10.2 B 3 Invention 103 ″ ″ X-5 (6.4g) ″ 2.6 10.3 A 4 Invention 104 ″ ″ X-8 (7.1 g) ″ 2.6 10.2 A 5 Invention105 ″ ″ nothing ″ 2.6 10.3 D 1 Comparative Example 106 nothing ″ nothing″ 2.6 10.3 D 1 Comparative Example 107 nothing ″ X-5 (6.4 g) ″ 2.6 10.3B 3 Invention

The antireflective films according to the invention were able to havesufficient surface resistance values by effects of the transparentconductive material, and delivered excellent adhesion and steel woolabrasion resistance by effects of the cross-linking site-formingcompounds. The surface resistance value in the comparative example wasequivalent to those in the invention, but adhesion and steel woolabrasion resistance were clearly inferior to those in the invention.

Example 2

Antireflective film Samples 201 to 205 having the compositions shown inTable 2 were made, and evaluated by the methods described above.

TABLE 2 Conductive Layer Cross-linking Low Steel Hard TransparentSite-Forming Refractive Integrated Wool Coating Conductive CompoundIndex Reflectance Abrasion Sample Layer Layer (Amount added) Layer (%)logSR Adhesion Resistance Note 201 H-2 C-1 X-1 (6.4 g) L-2 1.4 9.8 B 3Invention 202 ″ C-2 X-1 (6.4 g) ″ 1.4 9.8 A 4 Invention 203 ″ C-3 X-1(6.4 g) ″ 1.4 9.8 A 4 Invention 204 ″ ″ X-8 (7.1 g) ″ 1.4 9.8 A 5Invention 205 ″ ″ nothing ″ 1.4 10 D 1 Comparative Example

The antireflective films according to the invention were able to havesufficient surface resistance values by effects of the transparentconductive materials, and delivered excellent adhesion and steel woolabrasion resistance by effects of the cross-linking site-formingcompounds. The samples 202 to 204 in particular, wherein the polymerdopants having nonionic functional groups were used, made furtherimprovements in adhesion and steel wool abrasion resistance. Theseimprovements are thought to be attributable to increases in densities ofcross-linking sites inside the conductive layer and for interfaceadhesion between the conductive layer and its adjacent layer.

Example 3

Antireflective film Samples 301 to 303 having the compositions shown inTable 3 were made, and evaluated by the methods described above. As tothe conditions for curing the low refractive index layers used in thepresent example, however, 10 minutes' heating at 110° C. was notconducted.

TABLE 3 Conductive Layer Cross-linking Low Steel Hard TransparentSite-Forming Refractive Integrated Wool Coating Conductive CompoundIndex Reflectance Abrasion Sample Layer Layer (Amount added) Layer (%)logSR Adhesion Resistance Note 301 H-3 C-1 Oligomer a-1 (23.5 g) L-3 1.39.8 A 5 Invention 302 ″ ″ Oligomer a-2 (22.0 g) ″ 1.3 9.8 A 5 Invention303 ″ ″ nothing ″ 1.3 9.9 D 1 Comparative Example

The samples 301 and 302, which each used as the cross-linkingsite-forming compound the oligomer sol formed from a mixture of thecompounds represented by formulae (1) and (2) according to theinvention, were able to have sufficient surface resistance values byeffects of the transparent conductive material, and rated highest inadhesion and steel wool abrasion resistance. As a reason for this, it isthought that the hardness of the conductive layer was heightened byincreases in densities of cross-linking sites inside the conductivelayer and for interface adhesion between the conductive layer and itsadjacent layer and further by formation of cross-linked structures viaoligomers.

Example 4

Antireflective film Samples 401 to 406 having the compositions shown inTable 4 were made, and evaluated by the methods described above. As tothe conditions for curing the low refractive index layers used in thepresent example, however, 10 minutes' heating at 110° C. was changed to3 minutes' heating at 120° C.

TABLE 4 Conductive Layer Cross-linking Low Hard Transparent Site-FormingRefractive Integrated Steel Wool Coating Conductive Compound IndexReflectance Abrasion Sample Layer Layer (Amount added) Layer (%) logSRAdhesion Resistance Note 401 H-3 C-1 Oligomer a-1 (23.5 g) L-4 1.4 9.8 A5 Invention 402 ″ ″ Oligomer a-2 (22.0 g) ″ 1.4 9.8 A 5 Invention 403 ″″ X-1 (6.4 g) ″ 1.4 9.8 B 3 Invention 404 ″ ″ X-2 (6.4 g) ″ 1.4 9.8 B 3Invention 405 ″ ″ X-5 (6.4 g) ″ 1.4 9.8 A 4 Invention 406 ″ ″ X-8 (7.1g) ″ 1.4 9.7 A 5 Invention

All the samples 401 to 406 according to the invention were able to havesufficient surface resistance values by effects of the transparentconductive material, and delivered excellent adhesion and steel woolabrasion resistance by effects of the cross-linking site-formingcompounds.

Example 5 Preparation of Fine-Particle Titanium Dioxide Dispersion

As the fine-particle titanium dioxide, fine particles of titaniumdioxide that contained cobalt and had undergone surface treatment withaluminum hydroxide and zirconium hydroxide (MPT-129C, a product ofIshihara Sangyo Kaisha Ltd., TiO₂:Co₃O₄:Al₂O₃:ZrO₂=90.5:3.0:4.0:0.5 byweight) were used.

These particles in an amount of 257.1 parts by mass were admixed with41.1 parts by mass of Dispersant A illustrated below and 701.8 parts bymass of cyclohexanone, and dispersed by means of a Dynomill, therebypreparing a titanium dioxide dispersion having a weight-average particlesize of 70 nm.

Preparation of Coating Solution M-1 for Middle Refractive Index Layer

To 99.1 parts by mass of the foregoing titanium dioxide dispersion, 68.0parts by mass of a dipentaerythritol pentaacrylate-dipentaerythritolhexaacrylate mixture (DPHA), 3.6 parts by mass of a photopolymerizationinitiator (IRGACURE 907), 1.2 parts by mass of a photosensitizer(KAYACURE DETX, a product of Nippon Kayaku Co., Ltd.), 279.6 parts bymass of methyl ethyl ketone and 1049.0 parts by mass of cyclohexanonewere added and stirred. After thorough stirring, the resultant mixturewas filtered through a polypropylene filter having a pore size of 0.4μm, thereby preparing a coating Solution M-1 for a middle refractiveindex layer.

Preparation of Coating Solution H-1 for High Refractive Index Layer

To 469.8 parts by mass of the foregoing titanium dioxide dispersion,40.0 parts by mass of a dipentaerythritolpentaacrylate-dipentaerythritol hexaacrylate mixture (DPHA, a product ofNippon Kayaku Co., Ltd.), 3.3 parts by mass of a photopolymerizationinitiator (IRGACURE 907, a product of Ciba Specialty Chemicals Inc.),1.1 parts by mass of a photosensitizer (KAYACURE DETX, a product ofNippon Kayaku Co., Ltd.), 526.2 parts by mass of methyl ethyl ketone and459.6 parts by mass of cyclohexanone were added and stirred. Theresultant mixture was filtered through a polypropylene filter having apore size of 0.4 μm, thereby preparing a coating Solution H-1 for a highrefractive index layer.

Preparation of Coating Solution L-5 for Low Refractive Index Layer

The following Copolymer B according to the invention was dissolved inmethyl isobutyl ketone so as to have a concentration of 7 mass %, andthereto were added a silicone resin having methacrylate groups as itsends, X-22-164C (a product of Shin-Etsu Chemical Co., Ltd.), in aproportion of 3 mass % to the solid content and a photoradicalgenerator, IRGACURE 907 (trade name), in a proportion of 5 mass % to thesolid content. Thus, a coating Solution L-5 for a low refractive indexlayer was prepared.

(Making of Antireflective Film)

To a 80-μm-thick triacetyl cellulose film (TS-80UF, a product ofFUJIFILM Corporation), the coating solution for a hard coating layer andthe coating solution for a conductive layer as shown in Table 5 wereapplied in order of mention by using a coater having a slot die inaccordance with the same method as in Examples 1 to 4.

Further thereon, the coating solution for a middle refractive indexlayer, the coating solution for a high refractive index layer and thecoating solution for a low refractive index layer were put in successionby means of a gravure coater having three coating stations.

The coat for a middle refractive index layer was dried under conditionsthat the temperature setting was 90° C. and the time setting was 30seconds, and cured by UV irradiation under conditions that a 180 W/cmair-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) was usedin illumination of 400 mW/cm², in an exposure amount of 400 mJ/cm² andin an atmosphere with an oxygen concentration reduced to at most 1.0 vol% by purge with nitrogen. The middle refractive index layer after thecuring had a refractive index of 1.630 and a thickness of 67 nm.

The coat for a high refractive index layer was dried under conditionsthat the temperature setting was 90° C. and the time setting was 30seconds, and cured by UV irradiation under conditions that a 240 W/cmair-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) was usedin illumination of 600 mW/cm², in an exposure amount of 400 mJ/cm² andin an atmosphere with an oxygen concentration reduced to at most 1.0 vol% by purge with nitrogen. The high refractive index layer after thecuring had a refractive index of 1.905 and a thickness of 107 nm.

The coat for a low refractive index layer was dried under conditionsthat the temperature setting was 90° C. and the time setting was 30seconds, and cured by UV irradiation under conditions that a 240 W/cmair-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) was usedin illumination of 600 mW/cm², in an exposure amount of 600 mJ/cm² andin an atmosphere with an oxygen concentration reduced to at most 1.0 vol% by purge with nitrogen. The low refractive index layer after thecuring had a refractive index of 1.440 and a thickness of 85 nm. In thismanner, an antireflective film was made.

TABLE 5 Conductive Layer Cross-linking Site-Forming Middle High LowIntegrated Steel Hard Transparent Compound Refractive RefractiveRefractive Reflection Wool Coating Conductive (Amount Index Index IndexRate Abrasion Sample Layer Material added) Layer Layer Layer (%) logSRAdhesion Resistance Note 501 H-4 C-1 Oligomer a-1 (23.5 g) M-1 H-1 L-50.45 10.2 A 5 Invention 502 ″ ″ Oligomer a-2 (22.0 g) ″ ″ ″ 0.45 10.2 A5 Invention 503 ″ ″ X-1 (6.4 g) ″ ″ ″ 0.45 10.3 B 3 Invention 504 ″ ″X-2 (6.4 g) ″ ″ ″ 0.45 10.2 B 3 Invention 505 ″ ″ X-5 (6.4 g) ″ ″ ″ 0.4510.1 A 4 Invention 506 ″ ″ X-8 (7.1 g) ″ ″ ″ 0.45 10.2 A 5 Invention

Example 6 Saponification Treatment of Antireflective Film

The back of each of the antireflective film samples prepared in Examples1, 2, 3, 4 and 5 was saponification-treated under the conditionsdescribed below.

-   -   Alkali bath: 1.5 mol/dm³ of NaOH solution, 55° C.-120 sec    -   Fist washing bath: Tap water, 60 sec    -   Neutralizing bath: 0.05 mol/dm³ of Sulfuric acid, 30° C.-20 sec    -   Second washing bath: Tap water, 60 sec    -   Drying: 120° C., 60 sec        (Making of Polarizing Plate with Antireflective Film)

Iodine was adsorbed to a stretched polyvinyl alcohol film, therebymaking a polarizer. To one side of the polarizer, thesaponification-treated antireflective film was stuck with an adhesive ofpolyvinyl alcohol type so that the substrate (triacetyl cellulose) ofthe antireflective film faced the polarizer. A viewing angle increasingfilm having an optically-compensatory layer, Wide View Film SA12B (madeby FUJIFILM Corporation), was saponification-treated, and then stuck tothe other side of the polarizer with an adhesive of polyvinyl alcoholtype. In this manner, a polarizing plate was made.

As a result of evaluating TN-, IPS-, VA- and OCB-mode transmissionliquid crystal display devices which were each fitted with thepolarizing plate made in accordance with the invention, it wasascertained that the present polarizing plate allowed the making ofdisplay devices having excellent viewability, dust resistance andabrasion resistance.

<Liquid Crystal Display Device>

(TN-Mode Liquid Crystal Display Device)

TN-mode liquid crystal display with 20-inch diagonal screen: Instead ofthe polarizing plate provided on the viewer side of the model TH-20TA3(made by Matsushita Electric Industrial Co., Ltd.), one polarizing plateaccording to the invention (made from Sample 104 in Example 1) was stuckwith a pressure-sensitive adhesive of acrylic type so that itsoptically-anisotropic layer was situated on the liquid crystal cell'sside.

(OBC-Mode Liquid Crystal Display Device)

To the viewer's-side outermost surface of each of the OCB-mode liquidcrystal display devices disclosed in Examples 10, 15, 18 and 19 ofJP-A-2000-154261, the present Sample 301 made in Example 3 was stuckwith an adhesive of polyvinyl alcohol type.

(VA-Mode Liquid Crystal Display Device)

VA-mode liquid crystal display with 22-inch diagonal screen: Instead ofthe surface protective film provided on the viewer side of the modelTH22-LH10 (made by Matsushita Electric Industrial Co., Ltd.), thepresent Sample 204 made in Example 2 was laminated.

(IPS-Mode Liquid Crystal Display Device)

IPS-mode liquid crystal display with 22-inch diagonal screen: Instead ofthe surface protective film provided on the viewer side of the modelW20-LC3000 (made by Hitachi, Ltd.), the present Sample 402 made inExample 4 was laminated.

(Organic EL)

To the glass plate mounted on the surface of an organic EL displaydevice, the present Sample 405 made in Example 4 was stuck with apressure-sensitive adhesive.

Example 7 Thin TAC

A sample was prepared in the same manner as Sample 401 in Example 4,except that the thickness of the substrate was changed to 40 μm. As aresult of performing evaluations by the same methods as in Example 4, itwas ascertained that the antireflective film reduced in curling andexcellent in abrasion resistance and dust resistance was obtained.

Example 8 Coating on PET

Evaluations were made using as substrates of antireflective filmscommercially available optical PET films with easily-adhering layers,COSMOSHINE A4100 and A4300, products of Toyobo Co., Ltd., and the sameresults as mentioned above were obtained.

(PDP Image Display Device)

An antireflective film was made in the same manner as Sample 501 inExample 5, except that PET with an easily-adhering layer (COSMOSHINEA4100 made by Toyobo Co., Ltd.; thickness: 188 μm) was used as thetransparent substrate. The surface film was peeled off a 42-inch plasmadisplay devoid of a front plate (direct color-film system PDU-42H6A1made by Pioneer Corporation), and in place thereof the presentantireflective film was stuck with a pressure-sensitive adhesive. As aresult of performing evaluations on the plasma display device fittedwith the present antireflective film, it was ascertained that thedisplay device having excellent viewability, dust resistance andabrasion resistance was capable of being made.

This application claims foreign priority from Japanese PatentApplication No. 2006-316146, filed Nov. 22, 2006, the entire disclosureof which is herein incorporated by reference.

What is claimed is:
 1. An antireflective film comprising: a transparentsubstrate; a conductive layer formed from a composition including atransparent conductive polymeric material and a compound forming across-linking site, the compound forming a cross-linking site having aplurality of cross-linking reactive groups, at least one of whichcross-links with the transparent conductive polymeric material; and alow refractive index layer, wherein the transparent conductive polymericmaterial is a complex of a π-conjugated conductive polymer and a polymerdopant, wherein the compound forming a cross-linking site is a compoundhaving a first group capable of cross-linking with the polymer dopantand a second group having an ethylenically unsaturated double bond;wherein the first group is a glycidyl group, an oxetane group, or anisocyanate group; wherein the polymer dopant is a polyanionic polymerthat has anionic groups in a molecule which enable chemically oxidativedoping of the conductive polymer by the polymer dopant; and wherein theamount of the cross-linking site-forming compound is from 0.05 to 1.0g/m² and the surface resistance of the conductive layer is from 10⁴ to10¹¹ Ω/sq.
 2. The antireflective film of claim 1, further comprising: atleast one layer of a hard coating layer and an antiglare layer betweenthe transparent substrate and the conductive layer.
 3. Theantireflective film of claim 2, wherein the n-conjugated conductivepolymer is a homopolymer or copolymer made from one or two polymersselected from the group consisting of polypyrrole, polythiophene,poly(N-methylpyrrole), poly(3-methylthiophene), poly(-methoxythiophene),and poly(3,4-ethylenedioxythiophene).
 4. The antireflective film ofclaim 1, wherein the polymer dopant has at least one anionic group andat least one non-anionic group.
 5. The antireflective film of claim 4,wherein the π-conjugated conductive polymer is a homopolymer orcopolymer made from one or two polymers selected from the groupconsisting of polypyrrole, polythiophene, poly(N-methylpyrrole),poly(3-methylthiophene), poly(-methoxythiophene), andpoly(3,4-ethylenedioxythiophene).
 6. The antireflective film of claim 1,wherein the compound forming a cross-linking site has a groupcross-linking with the polymer dopant.
 7. The antireflective film ofclaim 6, wherein the π-conjugated conductive polymer is a homopolymer orcopolymer made from one or two polymers selected from the groupconsisting of polypyrrole, polythiophene, poly(N-methylpyrrole),poly(3-methylthiophene), poly(-methoxythiophene), andpoly(3,4-ethylenedioxythiophene).
 8. The antireflective film of claim 1,further comprising: a middle refractive index layer and a highrefractive index layer between the conductive layer and the lowrefractive index layer, wherein the middle refractive index layer, thehigh refractive index layer and the low refractive index layer arearranged in increasing order of distance from the transparent substrate,the middle refractive index layer has a refractive index of 1.5 to 1.7,the high refractive index layer has a refractive index of 1.7 to 2.1,and the low refractive index layer has a refractive index of 1.3 to 1.5.9. The antireflective film of claim 8, wherein the n-conjugatedconductive polymer is a homopolymer or copolymer made from one or twopolymers selected from the group consisting of polypyrrole,polythiophene, poly(N-methylpyrrole), poly(3-methylthiophene),poly(-methoxythiophene), and poly(3,4-ethylenedioxythiophene).
 10. Apolarizing plate comprising: a polarizer; and two protective filmssandwiching the polarizer therebetween, at least one of the twoprotective films being an antireflective film of claim
 1. 11. An imagedisplay device comprising a polarizing plate of claim
 10. 12. Theantireflective film of the polarizing plate of claim 10, wherein theπ-conjugated conductive polymer is a homopolymer or copolymer made fromone or two polymers selected from the group consisting of polypyrrole,polythiophene, poly(N-methylpyrrole), poly(3-methylthiophene),poly(-methoxythiophene), and poly(3,4-ethylenedioxythiophene).
 13. Theantireflective film of claim 1, wherein the π-conjugated conductivepolymer is a homopolymer or copolymer made from one or two polymersselected from the group consisting of polypyrrole, polythiophene,poly(N-methylpyrrole), poly(3-methylthiophene), poly(-methoxythiophene),and poly(3,4-ethylenedioxythiophene).
 14. The antireflective film ofclaim 1, wherein the surface resistance of the conductive layer is from10⁴ to 10⁵ Ω/sq.